Compiled by Norm Paratore - Gambrinus Stein Club
As probably everyone in the club knows, I collect primarily glass steins. Yes, I have the obligatory couple of Mettlachs, some silver pieces, an old piece of faience or two, and some old stoneware. But, glass is the driver and what floats my boat! And I got tired of going all over the web looking for definitions of terms that speakers continue to mention and I continue to forget.
So, one day I thought I’d take an hour to two and scourer the internet for a couple of sites that have definitions. Little did I realize what I was getting into! There are literally hundreds of sites with this information, from SCI to Ron Fox’s articles to the Corning Museum of Glass. I then started to remove some of the more modern uses and realized there is a bunch still missing. So, I asked Jim Sauer to review the list and add whatever he knew and was missing. Thanks to his help, many of the definitions are clearer in content and additional definitions I missed or had forgotten.
What I did was to copy all of the lists and then start sorting and culling out the definitions that have no real meaning to us or were duplicates. The end product is still so large it would take up the entire newsletter. And, this will always be a work in progress as other definitions are added.
As a side bar, I have finally found the definitive answer to the difference between flashed (stained), cased, and overlay glass. Several of the sites listed the definitions exactly the same with just minor word differences. One final note – some of the definitions are more of a historical nature that I thought some would find interesting.
Acid Etching - The process of etching the surface of glass with hydrofluoric acid. Acid-etched decoration is produced by covering the glass with an acid-resistant substance such as wax, varnish, or grease, through which the design is scratched using a needle or sharp tool. A mixture of dilute hydrofluoric acid and potassium fluoride is then applied to etch the exposed areas of glass. This leaves a matte finish and is usually a much lighter color to white appearance and not as deep as a copper wheel cut designed.
Acid etching was first developed on a commercial scale by Richardson's of Stourbridge, England, who registered a patent in 1857. An effect superficially similar to weathering may be obtained by exposing glass to fumes of hydrofluoric acid to make an allover matte surface. This method was popular in the 19th century.
Acid Polishing - The process of making a glossy, polished surface by dipping the object, usually of cut glass, into a mixture of hydrofluoric and sulfuric acids. The technique was developed in the late 19th century.
Agate Glass - See Calcedonio.
Air Twist - A type of decoration in the stems of 18th-century and later drinking glasses, made by twisting a glass rod embedded with threads of white or colored glass, columns of air (air twists), or a combination of all three.
Alabaster Glass - A type of translucent white glass, similar to opal glass, first produced in Bohemia in the 19th century. In the 1920s, Frederick Carder (1863-1963) introduced alabaster glass at Steuben Glass Works in Corning, New York. Carder's alabaster glass has an iridescent finish made by spraying the object with stannous chloride and then reheating it.
Alkali - In glassmaking, a soluble salt consisting mainly of potassium carbonate or sodium carbonate. It is one of the essential ingredients of glass, generally accounting for about 15-20 percent of the batch. The alkali is a flux, which reduces the melting point of the major constituent of glass, silica. Alkali is supplied in borax, soda, or potash.
Amalgam - An alloy of mercury and another metal; used with gold for gilding glass.
Amber - A yellow or yellowish-brown transparent glass coloring.
Amberina - A type of Art Glass that varies in color from amber to ruby red or purple on the same object. This shaded effect is due to the presence of gold in the batch. The object is amber when it emerges from the lehr, but partial reheating causes the affected portion to become red or purple. Amberina, developed by Joseph Locke (1846-1936) at the New England Glass Company in East Cambridge, Massachusetts, was patented in 1883.
Amberina Glass -Is a Collectable Art Glass. Was first developed by Joseph Locke at the
New England Glass Company, in the USA, and was patented by Locke in 1883. After
1888 Amberina glass was made by the Libby Glass Company. Today it is made
by contemporary glass works such as Boyd in the USA.
Amen Glass - A rare type of English wineglass with a drawn stem. The bowl is decorated by diamond-point engraving with verses from the Jacobite Hymn followed by the word "Amen," and with emblems associated with the Jacobite uprising of 1715. See Jacobite glass.
American Glass - Glass first made in the Americas was in Mexico in 1535 and Argentina in
1592 but neither glassworks succeeded due to the small population and lack of
Demand for glass items
increased until around 1730's. Finally the first successful American
glassworks was established by Caspar Wistar in Wistarburgh, New Jersey, 1738.
They produced bottles, window glass and tableware without any distinguishing
markings so it is hard to identify.
Ancient Glass - A term frequently used to mean all pre-Roman and ancient Roman glass.
Annagrün (German) - A type of yellowish-green glass colored by adding uranium oxide to the batch. Developed by Josef Riedel (1816-1894), who named it for his wife, Anna, this glass was made from the 1830s and 1840s. See also Uranium and Vaseline glass.
Annealing - Annealing is the gradual cooling of the outside and the inside of the molten glass slowly so the glass won’t cool too fast causing to fracture or break. The process of slowly cooling a completed object in an auxiliary part of the glass furnace, or in a separate furnace. This is an integral part of glassmaking because if a hot glass object is allowed to cool too quickly, it will be highly strained by the time it reaches room temperature; indeed, it may break as it cools. Highly strained glasses break easily if subjected to mechanical or thermal shock.
Annealing Oven - An Annealer is a gigantic oven that is computer-controlled to reduce the stress on the glass during the cooling period. A small computer runs a temperature versus time algorithm to reduce the stress present in all glass. Using a four-stage process with various soaks to insure the highest quality possible.
Antimony - A metallic oxide used to produce yellow coloring of glass.
Antique Glass- Is produced when a glass worker individually hand blows and rolls each sheet of glass. This process has been used since the middle ages and results in brilliant transparent glass with many striations and imperfections. The newer, mechanized procedures results in glass known as semi-antique, new antique, or artique® glass.
Apothecary Glass - Small hand blown glass medicinal bottles have been used for storing and
transporting medicines and the ingredients for medicines for nearly 2,000
years. The earliest ones were the Roman "unguentaria", sometimes
called "teardrop bottles" made by the thousands.
Apsley Pellatt Glass - The Falcon Glass House in Blackfriars and a large
showroom at St. Paul's Churchyard were part of the Pellatt and Green Company.
Apsley Pellatt IV joined his father's in business, in London around 1811 at the
age of 21. Apsley ran the company when his father died in 1826 and
changed the company name to Apsley Pellatt in the early 1830s.
Arsenic - An oxide of arsenic is used to improve color, transparency, and brilliance, often when producing opaque white glass or opaline.
Art Deco Glass - Named from an exhibition in Paris in 1925 (the Exposition des Arts
Decorative et industrial Moderns) where the finest French artists exhibited
their pieces in this new style.
Art Glass - A style of glass that relies on color, texture, and form for its visual appeal.
Art Nouveau Glass - Art Nouveau, a style of decoration popular in the
1890's and 1900's lasting until War broke out in Europe in 1914. It uses free
flowing motifs based on nature. The name Art Nouveau is derived from a
Paris gallery called 'Maison de L'Art Nouveau', which played a role in
displaying and popularizing this style.
Artistic Glass - A style of glass that uses surface decoration techniques such as engraving, cutting, or enameling.
Arts and Crafts Glass - The "Arts and Crafts" title came from the
Arts and Crafts Exhibition Society, established in 1887 to show off designers'
work in a range of materials and continued for some 50 years. As a reaction
against the extravagant, over-decorated Victorian taste and the worst features
of factory production.
Ashes - A residue of burnt materials from marine plants such as beech wood, ferns, or bone; used as an alkali in glassmaking.
At-the-fire - The process of reheating a blown glass object at the glory hole during manufacture, to permit further inflation and/or manipulation with tools.
Aurene Glass - A type of ornamental glass with an iridescent surface made by spraying the glass with stannous chloride or lead chloride and reheating it under controlled atmospheric conditions. Aurene glass was developed by Frederick Carder (1863-1963) at Steuben Glass Works in Corning, New York, in 1904.
Aventurine (from French aventure, "chance") - Translucent glass with sparkling inclusions of gold, copper, or chromic oxide, first made in Venice in the 15th century. Aventurine glass imitates the mineral of the same name, a variety of quartz spangled with mica.
Baccarat Glass - In 1765 the Bishop of Metz promoted industry in Baccarat, France. Verrerie de Sainte Anne in Baccarat made all kinds of utility glassware for windows, bottles and tableware. In 1815 they were purchased by Aime-Gabriel D'Artigues who wanted to re-establish his business in France. There on creating high quality lead-crystal glass. Baccarat is also famous for its paperweights, crystal glass tableware, and for lead crystal sculptures of animals and birds.
Backing - Holds together broken fragments of old glass by adhering to them by using a thin piece of glass with silicone or epoxy.
Batch - The mixture of raw materials (often silica, soda or potash, and lime) that is melted in a pot or tank to make glass. Cullet is added to help the melting process.
Battledore - A glassworker's tool in the form of a square wooden paddle with a handle. Battledores are used to smooth the bottoms of vessels and other objects.
Beading - The process of attaching an intermittent series of glass beads to decorate a glass surface.
Bent Glass (or Slump Glass) - Created by heating and forming it over a curved mold.
Berkemeyer (German) - A type of drinking glass, similar to a Römer, but with a funnel-shaped mouth. It was made in Germany and the Low Countries in the 16th and 17th centuries.
Beveled - A glass edge cut off at an angle. Light hits the edge, bends the light and produces a prismatic effect. A beveled edge width can vary but the most common width is ½ inch. A beveled edge is made by grinding off the on an angle of along flat edge of the glass. Curved edge bevels must be made by hand and straight-edged bevels are made with multiple machine grinding passes.
Biedermeier (style) - A style of decorative art favored by the German middle class between about 1820 and 1840. The name is derived from two fictional bourgeois characters, Biedermann and Bummelmeier, in the satirical verses of Ludwig Eichrod in a German journal featuring the two smug characters. During the period in which the Biedermeier style was popular, glassmaking revived in Bohemia, where new kinds of glass such as Lithyalin, elaborate flashed, wheel-engraved, and enameled glass were produced for middle-class consumers.
Blank – A solid piece of molten glass which can be used for future creation of other Art Glass work.
Blankschnitt (German, "polished cut") - A style of engraved decoration in which the relief effect is enhanced by polishing the ground part of the intaglio. Blankschnitt decoration is frequently found on glasses engraved in the German city of Nuremberg in the 17th and 18th centuries.
Blobbing - The technique of decorating hot glass by dropping blobs of molten glass onto the glass surface, usually of a different color or colors.
Block - A tool used for shaping molten glass into a “Block”. It is usually made of cherry wood and is “wet” while used with the hot glass. It is hollowed out to form a hemispherical recess. After it has been dipped in water to reduce charring and to create a "cushion" of steam, the block is used to form the gather into a sphere, prior to inflation.
Blocker - A glass worker that “blows” the first air bubble through a blowpipe. They then transfer the blow-pipe to the next glass worker, a Gaffer.
Blown Glass - It is made from blowing a glass bubble on the end of a hollow tube, a blowpipe. The artisan then shapes the glass into make a vase, bottle, glass or other objects by using iron tools, spinning, pinching and rolling. Another method places the bubble of glass into a hollow mold continuing to blown until it expands into all of the crevices of the mold.
Blower - A glass worker that blows the air through the blowpipe. Sometimes the gaffer may blow the air in order to have more control.
Blowing - The technique of forming an object by inflating a gob of molten glass gathered on the end of a blowpipe. The gaffer blows through the tube, slightly inflating the gob, which is then manipulated into the required form by swinging it, rolling it on a marver, or shaping it with tools or in a mold; it is then inflated to the desired size.
Blowpipe - A steel pipe which has an air way through the entire length of the pipe. The blower or gaffer blows in one end, the mouthpiece, and on the opposite end it has a built up area so the molten glass will gather and blow into a bubble.
Bohemia - The western glass region of Czechoslovakia, formerly an independent kingdom, later a region of the Austro-Hungarian Empire which became part of the newly formed country after World War 1 ended in 1918. Glass of every description has been produced there since the 14th century. The industry was nationalized by the Communist government in 1946. It is sad that after 600 years of glass making history, only two names are recognized by most American glass collectors. Those are Moser (pronounced Mózer) and Loetz(or Lötz).
Bohemian Designers include these and many more:
Zasche (at Gablonz)
Josef Rindskopf (Kosten)
Králík glassworks (Lenora)
Harrach works (Nový Svêt)
Carl Goldberg (Haida)
Ferdinand von Poschinger (Buchenau)
Fritz Heckert (Petersdorf, Silesia)
Josef Pallme-König (Kosten)
Meyr's Neffe (Adolfov)
Bohemian glass - A style of glass, usually wheel cut, originating from the Bohemian glass houses; Bohemia became part of Czechoslovakia in 1918. Bohemian glass is generally much lighter in weight and very noticeable when picked up.
Bone Ash - Ashes of bones used as a flux in the glass-making process that produces Opaline glass.
Bone Glass - see Milk glass.
Borsella (Italian) - A tong-like tool used for shaping glass. The borsella puntata has a pattern on the jaws, which is impressed on the glass.
Bottle Sheet Glass
Is a past method of glass forming which is comprised from four sides of a glass bottle that was blown into a square mold. A more current method is the cylinder-blowing method.
Bow Lathe - A primitive lathe powered by the use of a bow. The bowstring is looped around the spindle of the lathe and causes it to rotate as the bow is drawn backward and forward.
Broken-Swirl Ribbing - Mold-blown decoration that has two sets of ribs. This is made by blowing the gather in a vertically ribbed dip mold, extracting and twisting it to produce a swirled effect, and then redipping it in the same or another dip mold to create a second set of ribs.
Bubbles - While the molten glass is melting in the “pit” gases get trapped. The hotter the molten glass and the higher quality of the glass can greatly reduce this problem. Bubbles can be transmitted to the actual artwork during the gathering of the molten glass.
Brilliant-Cut Glass - Objects with elaborate, deeply cut patterns that usually cover the entire surface and are highly polished. In the United States, the vogue for brilliant-cut glass lasted from about 1880 to 1915.
Button - A very small clear piece of molten glass placed on the “working end” of the hot art piece to assure proper connection of the glass to the pipe and to avoid dropping and being damaged. Often a button may be used intentionally as part of the actual artwork as a visual enhancement.
Cable - A pattern resembling the twisted strands of a rope.
Calcedonio (Italian, "chalcedony") - Glass marbled with brown, blue, green, and yellow swirls in imitation of chalcedony and other banded semiprecious stones. Calcedonio was first made in Venice in the late 15th century.
Caliper - Tongs use to manipulate and control molten glass piece.
Cameo/Intaglio - A glass composed of two or more layers of glass, most often of contrasting colors, which are then carved through the surface with decorative designs. This ancient Roman technique was revived by the English in the late 19th century and English examples usually feature a white outer surface cut through to expose a single color background. English cameo often featured classical and botanical designs whereas the slightly later French cameo often featured more abstract naturalistic and landscape designs in more than two colors. Cameo carving can be done either by hand, a cutting wheel, or with the use of hydrofluoric acid, the hand-carved examples bringing higher prices.
Cane - A cross section of glass is made by pulling and stretching molten glass from both ends. It comes in several colors, patterns and strings range from fine filament to inches in diameter. The detail will continue to hold the precise shape even when scaled down to an almost invisible dimension.
Carnival Glass - Inexpensive pressed glass with vivid gold, orange, and purple iridescence, made in the United States between about 1895 and 1924. It is so called because it was frequently offered as fairground prizes.
Carving - Removing excess molten glass off of a working glass piece.
Cased Glass - Cased glass results from layering one color or glass over another. The process involves first making an outer casing by blowing a gather, knocking off one end, and opening the piece to form a cuplike shell. This shell is then placed in a metal mold and a second, different colored gather is blown into it. This combined piece is taken from the mold and reheated to fuse the two layers together. The outer layer is thick, which distinguishes it from the thin outer layer of flashed glass. This term is also improperly used in place of flashed or overlay to imply one layer of glass over another.
Layers may be created by using two different colors at the time the gather is placed on the blowpipe (by blowing or dipping), or by blowing a new color inside a piece after it has been formed. Sometimes as many as four different colors may be used. Sometimes you will see the inner and outer layers are clear, with the middle layer having the color. Other times the outer layer will be clear class.
Outer layers can be partially cut away to reveal color(s) of the previous "castings" beneath. The gaffer either gathers one layer over another gather, or inflates a gob of hot glass inside a preformed blank of another color. The two components adhere and are inflated together (perhaps with frequent reheating) until they have the desired form. Sometimes, the upper layer is carved, cut, or acid-etched to so that the underlying colors are allowed to show through the upper layers.
Cast Glass or Casting - Is created by pouring molten glass into a mold.
Cathedral Glass - Is usually a transparent glass of one color. Various patterns may be rolled onto the glass during its manufacture to diffuse light coming through the glass. Common patterns include hammered, granite, ripple, seedy, double rolled, and rough rolled.
Chalk glass - A colorless glass containing chalk, developed in Bohemia in the late 17th century. Vessels of thick chalk glass were often elaborately engraved.
Chill-Mark - Any
instrument used on a hot glass surface there is a potential for it to leave a
cooled surface that refracts light differently and these marks are called
Chord - Lines of clear glass with slightly different expansion coefficient enhance refract light at different rates.
Chunked - A piece of glass that has been badly damaged.
Chromium - A metallic agent used in glass to produce a yellowish–green color.
Cire perdue (French, "lost wax") - See Lost wax casting.
Clamp - A tool sometimes used instead of a pontil to hold the closed end (usually the bottom) of a partly formed glass vessel while the open end (usually the mouth) is being shaped. See also Gadget.
Clapper - A tool consisting of two rectangular pieces of wood joined at one end by a leather hinge. There is an aperture in one of the pieces of wood, and this holds the stem of a goblet or wineglass while it is being mad e. The clapper is used to squeeze a blob of glass in order to form the foot.
Claw beaker - A beaker decorated with claw, or trunk-like protrusions, made by applying blobs of hot glass that melted the parts of the wall to which they were attached. The blobs were then blown outward and manipulated to resemble hollow claws. Claw beakers were made in Europe between the fifth and seventh centuries A.D. Similar decoration was made in Germany in the 16th century.
Cobalt - A metallic agent used in glass to produce dark and light shades of blue. Cobalt oxide is mixed with molten glass, cooled, and then ground into powder to produce a coloring agent for glass enamel. This enamel is also used in pottery and porcelain glazes.
Cold Painting - A decorative technique utilizing lacquer colors or oil-based pigments applied to glass, porcelain, or stoneware, with no subsequent firing. Very susceptible to wear and rarely found intact on old pieces. (See Enameled Glass)
Cold Working - Any working, without heat, on the surface of
a finished piece of glass once annealing process is completed. This is often
accomplished by grinding, surfacing
Collar - It is a ring used to hold the cane glass in place while working a piece.
Copper disks - Wheels of various sizes and rim profiles are rotated on a spindle. Slurry, a mixture of oil and abrasives such as Carborundum® (in the past, emery was frequently used), is applied to the edge of the wheel. The wheel presses the abrasive against the glass so that it removes the surface by grinding.
Copper oxide - A metallic agent used in glass to produce turquoise blue or green.
Copper Wheel Engraving - When talking about glass steins, most of what we call “etched” are actually made using copper wheels of various sizes and an abrasive in slurry to grind a design into the surface of the glass. See Wheel Engraved.
Coralene - The application of tightly spaced beads onto a glass surface to give the decoration a coral–like appearance and texture.
Cord - Streaking to a slight color haziness normally caused by deficiencies in the glass quality product.
Core - The form to which molten glass is applied in order to make a core-formed vessel. In pre-Roman times, the core is thought to have been made of animal dung mixed with clay.
The technique of forming a vessel by trailing or gathering molten glass around a core supported by a rod. After forming, the object is removed from the rod and annealed. After annealing, the core is removed by scraping.
Cracking off - The process of detaching a glass object from a blowpipe or pontil.
Crackle Glass - It is created by dipping a molten cylinder of glass into water which causes the exterior of the glass to crack but the molten interior holds together. The cylinder is sliced down the side, flattened and the crackle textures are rolled into glass.
Cranberry - Transparent glass with a pinkish-red coloring.
Cristallo - Cristallo is Italian soda glass and is usually pale yellow or clear. It was made with a plant called barilla which grows in the salt marshes. The barilla made the glass very malleable and could be formed into a large variety of shapes. It was thin and brittle and suited only for diamond point engraving. It was popular in the 15th and 16th centuries until lead glass took over. Today chemical soda has basically taken the place of the plant in glassmaking.
Crizzling or crisseling - A chemical instability in glass caused by an imbalance in the ingredients of the batch, particularly an excess of alkali or a deficiency of stabilizer (usually lime). The instability of the glass results in an attack by atmospheric moisture, which produces a network of cracks in the surface. Crizzling can be slowed or perhaps even halted, but it cannot at present be reversed.
Crosshatching - A term generally used in discussing Brilliant Period cut glass. It refers to a cut design of parallel or crossed fine lines.
Crown Glass - Rotating the glass as it is blown, a by product is a disk shape with a crown, in the center. This is also called a Roundel.
Crystal Glass - An abused term, referring to clear, colorless glass. Now a generic term generally used today when referring to fine quality glass stemware produced since the early 20th century. Derived from the Italian term cristallo referring to delicate, clear Venetian blown glass produced since the 14th century. Another misnomer is that you can tell the quality of glass by flicking it with your fingernail and listening to the sound. That is really a test of the lead content in the glass and can lead to cracked glass.
Remember - Crystal is formed by nature and is clear like glass but rare and very expensive. Glass is man-made.
Cullet - The cost of the raw materials in a batch of colorless glass was offset with the addition of cullet, which was the waste and broken glass from previous batches of the same type. Cullet reduced the amount of fuel, and the cost, needed to fuse a batch into molten glass, and provided a means to reuse expensive ingredients, such as red lead, in the form of broken scraps and finished glass that had been rejected as imperfect. Cullet acted as a flux and speeded up the fusing process and often comprised from 25 to 50% of the total weight of the batch. It was necessary to fuse the batch as quickly as possible to clear the molten glass of all the trapped air and gases that formed undesirable bubbles and seeds. The inclusion of cullet did not affect the quality of the finished glass. (This is debated and some sites say it does reduce the quality.) Waste and broken colored glass usually was not reused as cullet, as color control and consistency without any variation was necessary.
Cut Glass - Glassware that is decorated with facets, grooves, and depressions made by cutting with rotating wheels of iron or stone; once the pattern is cut, it needs to be polished.
Cut-to-Clear - Cutting however many layers needed to create the desired effect in the glass by removing a portion of the outer layers to show the underlying glass layers.
Cutting - The technique whereby glass is removed from the surface of an object by grinding it with a rotating wheel made of stone, wood, or metal, and an abrasive suspended in liquid. See also copper-wheel engraving, carving, and wheel engraving.
Cylinder glass - Window glass made by inflating a large gather and swinging it until it forms a cylinder. The cylinder is then detached from the blowpipe, and both ends are removed with shears. Next, the cylinder is cut lengthwise, reheated, and either tooled or allowed to slump until it assumes the form of a flat sheet. After annealing, the sheet is cut into panes.
Decolorizing Agent - A mineral used to counteract the greenish or brownish color in glass caused by iron particles in the silica (sand) or from iron in other ingredients in the batch. Glass in its natural state is not colorless and requires an agent. Sometimes you will see a slight color tint to glass caused by adding too much of one of the agents.
Diamond Air Trap - Decoration consisting of bubbles of air trapped in the glass in a diamond-shaped pattern. This is achieved by blowing a gather of glass into a mold with projections of the desired design, withdrawing it, and covering it with a second gather, which traps pockets of air in the indentations. This technique was patented by W. H., B. & J. Richardson of England in 1857. (See Pegging)
Diamond-point Engraving - The technique of decorating glass by scratching the surface of the glass with a tool using a diamond nib. Introduced by the Venetians in the 16th century, and in England during the 16th century also. I reached its greatest artistic heights in the Netherlands during the 17th century. See Stippling.
Diatreta - A term used by Frederick Carder (1863-1963) to describe openwork objects, which he made by lost wax casting.
Diminishing Lens (Reducers) - Polished concave circular lenses that concentrate light and reduce the image; usually found on Bohemian pieces on the side opposite from the central scene.
Dip Mold - A cylindrical, one-piece mold that is open at the top so that the gather can be dipped into it and then inflated. See also Optic mold.
Enamel - A combination of frit, metallic oxides, and oil added to the surface of glass that fuses to the glass surface when fired and becomes part of the glass. The medium burns away during firing in a low-temperature muffle kiln (about 965°-1300° F or 500°-700° C). Sometimes, several firings are required to fuse the different colors of an elaborately enameled object.
Enamel Firing - Enamel colors are mixed with a flux to lower the fusing point below that of the glass object; the lower temperature is necessary to fuse the enameling to the glass object without damaging its form.
Enamel Overlay - The process by which a glass body is enameled with a heavy layer of one color giving the appearance of a glass overlay; this enameling can be cut through to reveal the layer underneath.
Enameled Glass - Decorated with particles of translucent, usually colored, glass or glass-like material, which fuses to the surface under heat. Multicolored designs as well as monochrome coatings can be created. Painting in colored enamels was popular on Venetian glass from the late 15th century and became fashionable in England in the mid-18th century. The best-known English enamellers were the Beilby family. There are two types of enameling:
Enameled Line Gilding - A decorative technique whereby enameled lines are painted and fired onto a glass body to form the outline of a design. After cooling, the entire design is painted with gold and fired on. This technique produces raised outlines and gives the decoration a three-dimensional effect.
Engraving - Glass can be engraved with numerous patterns using various size bits. Freehand engraving is a task which requires precision, an eye for proportion, and a steady hand. The design is produced step by step. The proper bit must be chosen for each detail in the design. This means that a complicated design requires the use of several different bits. Because the design usually consists of flowers, leaves, bows, and so forth, the process is sometimes called "blomslipning" or "floral engraving" in Swedish. There are four types of engraving:
Faceted Glass - Glass containing flat surfaces ground onto the body. A prism would be considered a faceted decoration.
Façon de Venise (French, "style of Venice") - Glass made in imitation of Venetian products, at centers other than Venice itself. Façon de Venise glass was popular in many parts of Europe in the 16th and 17th centuries.
Filigree Glass - Glass with internal decoration of threads (generally twisted) imbedded within the glass.
Fire Clay - Clay capable of being subjected to a high temperature without fusing, and therefore used for making crucibles in which glass batches are melted. Fire clay is rich silica, but contains only small amounts of lime, iron, and alkali.
Fire Polishing - The reintroduction of a vessel into the glory hole to melt the surface and eliminated superficial irregularity or dullness. Also used to round the sharp edges, such as the lip of a beer stein. A process used to finish mold-blown and pressed glass where a piece is reheated just enough to smooth out the mold seams without distorting the overall pattern
Flameworking - The technique of forming objects from rods and tubes of glass that, when heated in a flame, become soft and can be manipulated into the desired shape. Formerly, the source of the flame was an oil or paraffin lamp used in conjunction with foot-powered bellows; today, gas-fueled torches are used.
Flashing / Flashed glass (Intarsia) - The application of a very thin layer of glass of one color over a layer of contrasting color. This is achieved by either painting over the first layer or dipping a gather of hot glass into a crucible containing hot glass of the second color and then being refired in a muffle kiln to harden. It was probably more often painted over because the thickness could be controlled. The effect desired was not to the thickness of an overlay but to allow contrasting colors and to enable the artists to cut intricate designs.
The outer layer is generally too thin to be worked in relief and is mostly just cut back to show the under lying glass. "Flashing" is sometimes used (erroneously) as a synonym for casing or cased glass, as well as overlay glass.
Similar in its artistic ends to cased glass, flashed glass involves the application of a very thin layer of glass onto an object of a different color. The outside layer is then cut or etched in some fashion, leaving the underlying color exposed to form the design. We frequently see ruby flashed beer steins which have been cut to the clear base glass. Flashing is so thin that over the course of 100+ years it is frequently found with scratches going completely through the top layer. This also applies to “stained glass.”
Fleabite - Tiny fairly round little nick no larger than the size of a pencil point most frequently found on the rim or base of a stein or glass piece. More accurately described as a pinpoint nick.
Fluted or Flute Cuts - Glass that has evenly spaced flutes running parallel to each other around the body.
Flux - A substance that lowers the melting temperature of another substance. For example, a flux is added to the batch in order to facilitate the fusing of the silica. Fluxes are also added to enamels in order to lower their fusion point to below that of the glass body to which they are to be applied. Soda is added to Venetian glass, potash is added in Bohemian glass, wood ash is added in forest glass, and lead oxide is added in lead crystal.
Folded foot - A foot with the outer rim folded back and fused to the glass, making a double thickness at the edge, similar to a hem on a cloth garment.
Founding - The initial phase of melting batch. For many modern glasses, the materials must be heated to a temperature of about 2450° F (1400° C). This is followed by a maturing period, during which the molten glass cools to a working temperature of about 2000° F (1100° C).
Free hand blown – See Hand blown glass.
Frit or Fritt - Previously made glass which has been ground into a powder and mixed with oxides and oil to give enamel its glass base. It is then painted onto the surface and fired again to fuse and become one with the underlying glass body. This method can be used to make extraordinarily complicated and beautiful designs.
Fumed Glass (or fuming technique) - Glass is exposed to acid fumes which give the surface an iridescent look popularized by the Art Nouveau glassmakers.
Furnace - An enclosed round brick structure for the production and application of heat. In glassmaking, furnaces are used for melting the batch, maintaining pots of glass in a molted state, and reheating partly formed objects at the glory hole. In early times it was fueled by wood, later by coal, and now by gas.
Fusing - (1) The process of founding or melting the batch; (2) heating pieces of glass in a kiln or furnace until they bond (see casting and kiln forming); (3) heating enameled glasses until the enamel bonds with the surface of the object.
Gadget - A metal rod with a spring clip that grips the foot of a vessel and so avoids the use of a pontil. Gadgets were first used in the late 18th century.
Gaffer (English, corruption of "grandfather") - The master craftsman in charge of a chair, or team, of hot-glass workers.
Gather - A mass of molten glass (sometimes called a gob) collected on the end of a blowpipe, pontil, or gathering iron; (verb) to collect molted glass on the end of a tool.
Gathering iron - A long, thin rod used to gather molted glass.
Gilding - Gold decoration was applied to the surface of the glass in a number of different ways. The most permanent method of gilding was by firing the gold onto the surface of the glass. An alternative method was oil-gilding, which involved applying a gold powder or leaf onto an oil base and burnishing. Gilding applied using this method is easily rubbed off.
Glass - A homogeneous material with a random, liquid like (non-crystalline) molecular structure. The manufacturing process requires that the raw materials be heated to a temperature sufficient to produce a completely fused melt, which, when cooled rapidly, becomes rigid without crystallizing.
Glass Blower’s Bench - A chair with iron arms which allows the blower to roll the blow pipe back and forth spinning molten glass; the centrifugal force of the spinning maintains the shape of the glass while it is being worked.
Glass Blower’s Soap - A term used by glass blowers for the decolorizing agent.
Glass Bubbles - Hand made glass almost always has a few small bubbles. Good quality art glass normally only has a few bubbles unless they are part of the design. Bubbles can often be found in very old glass or in the work of novice glassmakers. (See Pegging)
Creating the effect of bubbles can also be achieved by:
· Adding chemicals to the glass batch and the reactions will produce random air bubbles during the melting process.
· By pushing into molten glass with a spike will create a single bubble, an internal sphere.
· By pushing a tool with rows of spikes will produce a stream of such bubbles in a line.
Glass Pot - A clay pot in which the glass batch is melted within the furnace.
Glass Relief - A precast figural glass forms such as acorns, bees, birds, fish, etc. that are applied to the glass body; they are usually enamel decorated.
Glory Hole - A hole in the side of a glass furnace, used to reheat glass that is being fashioned or decorated. The glory hole is also used to fire-polish cast glass to remove imperfections remaining from the mold.
Gob - See Gather
Goblet - A drinking vessel with a bowl that rests on a stemmed foot.
Ground Pontil - Ground and polished pontil mark leaving a hollow, smooth depression in the center of the underside of the base.
Hand Blown Glass - The process of taking a gathering of molten glass on the end of a blow pipe and working it into a ball on the marver so it can be blown and shaped with hand tools.
Handkerchief Test - Plain early glass has sometimes been decorated with later engraving to make it seem more valuable. To check the decoration is authentic, drop a white handkerchief in the glass - old engraving will look dark and grey against the cloth, while new engraving will seem white and powdery. A handkerchief or white cloth is also useful to show up the color of the glass itself.
Highlighted Transfer Enamel - The use of the Transfer Enamel process with the addition of minor hand painting (see Transfer enamel).
Historismus Glass - A German term referring to late 19th century glass made in the style of 17th century and earlier periods.
Hyalith - A dense, totally opaque glass of either wax-seal red or black that is usually facet cut and/or gilded.
Hydrofluoric Acid - A colorless, highly corrosive acid that attacks all silicates; used to etch the surfaces of glass and porcelain. Pure hydrofluoric acid dissolves glass, leaving a brilliant, acid-polished surface.
Ice Glass - An effect caused by submerging molten glass in cold water, causing the entire surface to crack; the glass is then reheated and the cracks are smoothed over; also known as Crackled glass.
Internal Decoration - An apparent decoration inside glass, created by mixing, inserting, or other forms of manipulation; examples are Aventurine, Filigree, and Sulphides; not to be confused with surface decorations.
Inlay - Any object embedded in the surface of a larger object, as in the lid of a stein. See also Marquetry.
Intaglio (Italian, "engraving") - A method of engraving whereby the ornamentation is cut into the object and lies below the surface plane. The German name for this technique is Tiefschnitt.
Iridescence - The rainbow like effect that changes according to the angle from which it is viewed or the angle of incidence of the source of light. On ancient glass, iridescence is caused by interference effects of light reflected from several layers of weathering products. On certain 19th- and 20th-century glasses, iridescence is a deliberate effect achieved by the introduction of metallic substances into the batch or by spraying the surface with stannous chloride or lead chloride and reheating it in a reducing atmosphere.
Iridized Glass - Metallic salts are applied to opalescent or cathedral glass, to create vivid mother-of-pearl colors reflecting off the glass surface.
Jacobite Glass - A 17th-century English drinking vessel used for toasting Prince Charles Edward Stuart ("Bonnie Prince Charlie"). The Jacobites were supporters of the exiled King James II, who abdicated in 1698, and of his descendents James Edward Stuart (the "Old Pretender") and his son Charles Edward Stuart (the "Young Pretender"). Before the defeat of the Young Pretender in 1746, Jacobite glasses were usually engraved with the English rose, representing the Crown, and an optimistic motto such as "Redeat" ( Latin, "May he return"). After 1746, glasses at first bore cryptic symbols and messages, but later secrecy was abandoned. See also Williamite glass.
Jugendstil (German, "youth style") - See Art Nouveau.
Kiln - An oven used to process a substance by burning, drying, or heating. In contemporary glass working kilns are used to fuse enamel and for kiln forming processes such as slumping.
Kiln Forming - The process of fusing or shaping glass (usually in or over a mold) by heating it in a kiln. See slumping.
Lacy-pattern Glass - Nineteenth-century pressed glass whose patterns included extensive stippling to produce a bright, lacelike effect that conceals wrinkles caused when the cold plunger of the pressing machine came into contact with the hot glass.
Lead Glass - Glass with a high lead content in the batch, which lowers the melting point and softens it for cutting; Lead Crystal was also used during the brilliant period of cut glass. This glass was harder and allowed deeper, crisper cutting.
Lehr (or leer) - The oven used for annealing glassware. Early lehrs were connected to the furnace by flues, but the difficulty of controlling heat and smoke made this arrangement impracticable. Later lehrs were long, brick-lined, separately heated tunnels through which the glass objects were slowly pushed; the glass remained in the lehr for several hours, while it was gradually reheated and then uniformly cooled. Today, lehrs work on a conveyor belt system.
Lime - Calcined limestone, which, added to the glass batch in small quantities, gives stability. Before the 17th century, when its beneficial effects became known, lime was introduced fortuitously as an impurity in the raw materials. Insufficient lime can cause crizzling.
Lithyalin (from Greek lithos, "stone") - A type of glass, developed in Bohemia by Friedrich Egermann (1777-1864), that is opaque and has a marbled surface resembling semiprecious stones.
Lost Wax Casting - A technique adapted from metalworking. The object to be fashioned in glass is modeled in wax and encased in clay or plaster that is heated. The wax melts and is released through vents or "gates," also made of wax, which have been attached to the object before heating; the clay or plaster dries and becomes rigid. This then serves as a mold, into which molten or powdered glass is introduced through the gates. If powdered glass is used, the mold is heated in order to fuse the contents. After annealing the mold is removed from the object, which is then finished by grinding, fire polishing, or acid etching.
Luster - (1) A shiny metallic effect made by painting the surface with metallic oxides that have been dissolved in acid and mixed with an oily medium. Firing in oxygen-free conditions at a temperature of about 1150° F (600° C) causes the metal to deposit in a thin film that, after cleaning, has a distinctive shiny surface. (2) A glass lighting device, such as a candelabrum or candlestick, decorated with hanging prismatic drops.
Manganese Oxide - A metallic oxide used to color glass amethyst or purple hues; mixed with cobalt it produces black hyalith glass; also used as a decolorizing agent.
Marble Glass – see Lithylin.
Marquetry - A decorating technique whereby pieces of hot glass are applied to still molten glass and marvered into the surface, creating an inlaid effect. After the glass is cooled, it is possible to further emphasize these areas by carving and engraving. See also Inlay.
Marver (French marbre, "marble") - An iron or marble table or other smooth flat surface, on which softened glass is rolled when attached to the blowpipe or pontil in order to smooth it or to consolidate applied decoration.
Mary Gregory style - A style of enameling on glass done only in white and generally picturing Victorian children.
Medallion – Generally denotes a raised section of the glass that can either be plain, have initials cut into it, or a building/scene.
Melt - The fluid glass produced by melting a batch of raw materials.
Metal - A term glassmakers often use when referring to glass.
Metallic oxides - Used as pigments to color glass and to make enamel colors used to decorate glass surfaces.
Milk Glass - An opaque glass with the appearance of white porcelain; its opacity and color are due to the addition of tin oxide, which is also used to give faience its opaque white glaze covering.
Mold - A form, normally made of wood or metal, used for shaping and/or decorating molten glass. Some molds (e.g., dip molds impart a pattern to the parison, which is then withdrawn, and blown and tooled to the desired shape and size; other molds are used to give the object its final form, with or without decoration.
Mold Blown - Molten glass that is blown into metal or wood molds, eliminating some or all shaping with hand tools; the glass takes on the shape of the mold into which it is blown.
Molten Glass - Glass in a melted state after the ingredients have been fused at a high temperature, liquefying the batch. It is then allowed to cool until it is plastic and shapeable. It is sticky and will adhere to an iron blow pipe or other glass object already heat-softened.
Mosaic Glass - Objects made from preformed elements placed in a mold and heated until they fuse. The term "mosaic glass" is preferable to "millefiori," except in the case of Venetian or faço n de Venise glass.
Muffle Kiln - A low-temperature kiln for retiring glass to fuse enamel, fix gilding, and produce luster. (See Kiln)
Needle Scratched (or Engraved) - Needle engraving was a method of scratching through the surface of staining after the color pigment had been applied and dried, but before it was fired in the limited heat of a muffle kiln, using a sharp pin-like tool. After firing, the pigment became a color and set into the glass surface, it was removed and the burned ash on the staining was cleaned and the color was polished into a high gloss.
If you collect glass steins, take a look at your stained glass steins and I'm sure you will find some examples of needle engraving on at least a few. It was fairly common. If the needle engraving had been done after the firing, the tip would have scratched the glass, which didn't happen. Look for repeated patterns of leaves on your stained pieces and you will see that the outline can be the same, but the curved lines on the leaf pedals are all rather different, from the needle engraving. It makes the leaves look different on the finished color. This also says something else, a stencil (or template) was used for this purpose, and painted over with a brush.
Opal glass - Glass that resembles an opal, being translucent and white, with a grayish or bluish tint. Is done by a fired-on finish that imparts a milky iridescence.
Opalescent Glass - Is created when one or more colors mixed with opal white glass to produce varying degrees of opacity. It is rolled by machine or hand rolled to produce glass of uniform thickness. One sheet may contain as many as five colors. Patterns include double rolled, granite, ripple, and mottled. Wispy opals have light, feathery streaks of white opal.
Opaque Enamel - Enamel that prevents the glass under color from showing through.
Opaque Glass - Glass that does not allow light to pass through it, showing little fire or translucence when held to light.
Overlay - A small piece of concentrated glass color is placed on the pipe and covered with clear glass, shaping it like an egg. In the meantime, another glassblower makes the overlay color --the color that is meant to be on the outside is put on the pipe. Then one color is placed on top of another. After reheating the underlay is attached with the overlay. The overlay is placed on top of the underlay (like a stocking) and shaped like a vase or whatever the desired form.
The overlay can then be cut back to show the underlying glass or a scene can be done by varying the depth of cuts to the overlay glass. In more modern times, a pattern is made by drawing on the sandblaster tape, cutting out the pattern and placing it on the vase. The piece is sandblasted around the tape thereby removing all the different layers of colors. Finally all the details on the piece are engraved.
Painting - The process by which enamel or stain is applied to glass and is then reheated in a muffle kiln. After firing, the pigment became a color and set into the glass surface, it was removed and the burned ash on the staining was cleaned and the color was polished into a high gloss.
Parison (French, paraison) - A gather, on the end of a blowpipe, which is already partly inflated.
Pegging - Air trapped bubbles, or air locks, in the bases of glass steins are known as "pegging." A random pattern means that indentations were applied with a pointed tool one at a time before being covered with a small gather of molten glass to form the finished base. A definite circle, or several circles, of bubbles in the base indicates an iron mold was made with a series of studs in the base to make the indentation pattern, thus speeded up the whole process.
Pick-up Decoration - A technique whereby a hot parison is rolled in chips of glass, which are picked up, marvered, and inflated.
Pincers - A pliers-like tool used for inserting pinched decorations on handles, rims, etc.
Plastic - Glass in the molten state, in which it is easily modeled and shaped.
Polished cut – polishing the matte surface of intaglio engraved glass using soft disks or brushes made of leather or cork, enhancing the effect of the cut.
Polishing – the process of giving glass a smooth, brilliant surface after it has been cut or engraved; first it is polished with a fine-grained stone wheel, then with a finer wheel made of lead, wood or cork. It is done when it is cold by holding it against a rotating wheel fed with a fine abrasive. Glass can also be polished with more modern hand-held tools.
Pontil or Pontil Mark - A wad of hot glass is applied to a pontil rod and then applied to the base of a vessel to hold it during manufacture to make it easier to handle during the final shaping and finishing. When snapped off the pontil rod it often leaves an irregular or ring-shaped scar on the base when removed. This was usually ground, smoothed, and polished from the 1860s onward. This mark or scar is called the "pontil mark."
Pontil rod - A solid iron rod to which a partly made glass object is transferred from the blow pipe; here the final shaping, finishing of the neck, and attachment of handles or other applied glass takes place. A small gathering attaches the object to this rod.
Pot - A fire clay container placed in the furnace in which the batch of glass ingredients is fused, and kept molten. The glass worker gathers directly from the pot.
Potash - Potassium carbonate. It is an alternative to soda as a source of alkali in the manufacture of glass. Potash glass was particularly suited to cutting and engraving.
Potash glass - Potash (potassium carbonate) was used as flux in Germany and Bohemia. You could obtain it by burning the residue of wine or by burning beech wood. Because it was harder than soda glass (Venetian), and because it could be made thicker, it is well suited for engraving. It is also more brilliant and is still used as an ingredient in lead glass.
Pressed glass - Glassware formed by placing a blob of molten glass in a metal mold, then pressing it with a metal plunger or "follower" to form the inside shape. The resultant piece, termed "mold-pressed," has an interior form independent of the exterior, in contrast to mold-blown glass, whose interior corresponds to the outer form. The process of pressing glass was first mechanized in the United States between 1820 and 1830.
Prism - Glass with multiple flat facets that have been stone wheel cut and polished, similar to facets found on diamonds.
Prunt - A prunt is a separate dab or blob of glass which has been applied as decoration to the exterior of a glass object. Prunts may be found in a variety of shapes, including a nipple, a starburst or a raspberry, and are frequently in a different color than the base glass. They also afford the user a more firm grip in the absence of a handle.
Punty – see Pontil.
Quincunx (Latin, "five-twelfths) - An arrangement of five objects in a square or rectangle, with one at each corner and one in the middle, like the five spots on dice. Prunts and other motifs are sometimes arranged in a quincunx pattern.
Reducers – see diminishing lens.
Reeded - Glass with uniform parallel ridges. Any dimension given specifies the spacing, for example, "1/2 inch Reeded glass."
Relief Enamel - A raised decoration achieved by applying heavy or multiple layers of enamel; also refers to the application of porcelain relief to the glass body, attaching it with a low-fired adhesive and then encasing it with an enameled decoration.
Relief gilding – a decorative technique where a thick enamel design is painted onto glass and then fired in a kiln; after cooling, it is over coated with gold and refired, resulting in an overall gold relief design.
Removal of the Piece and Polishing the Rim - The top or bowl of the glass is removed from the pipe by first etching a line with a diamond bit around the glass at the desired height. Then the glass is heated with a gas flame which causes expansion of the material and the glass breaks off around the cut. A grinder with a water supply is then used to grind down the sharp and somewhat uneven edges around the lip of the glass. To make the edge round and smooth, it is reheated in a special furnace, usually called a glory hole, which heats or melts the glass to a temperature of approximately 1200 degrees Celsius (2192 degrees Fahrenheit).
Resist - The wax preparation used to protect the glass surface from the acid used during the Acid Etching process; surfaces not covered with the resist are etched by the acid (see Acid etching).
Rigere or Rigaree - Applied ribbon-like, glass bands or crimped decoration done while still in the molten stage. Used to highlight some types of Victorian Art Glass. It is a form of appliquéd decoration. Most commonly used on the base of the stein.
Rock Crystal - A quartz-like material resembling solid glass but seldom used because of its rarity and high cost.
Rock enamel - Two possible meanings: (1) a cut and faceted clear quartz stone; (2) a style of 19th century glass cut to resemble clear quartz stone.
Römer (German) or Roemer (Dutch) - A drinking vessel of goblet form with an ovoid mouth, a cylindrical body, and a wide conical foot tapering upwards and diminishing in size until it reaches the side of the bowl. The body is usually decorated with prunts.
Ruby Glass - Glass with a blood-red coloring, achieved by adding copper, gold, or selenium.
Sand - The most common form of silica used in making glass. It is collected from the seashore or, preferably, from deposits that have fewer impurities. For most present-day glassmaking, sand must have low iron content. Before being used in a batch, it is thoroughly washed, heated to remove carbonaceous matter, and screened to obtain uniformly small grains.
Sand blasting - Sand particles directed at the glass surface at high velocity to etch a design.
Sandwich Glass - Early pressed glass from Sandwich, Massachusetts and prized by collectors today.
Schwartzlot - A German term for black enamel that was used on glass from 1650-1750, most often by Hausmalers (freelance painters) outside the factories.
Seam - A ridge on a piece of glass caused by the minute crack between two parts of the mold. Same as a mold mark.
Seeds - Seeds are tiny air bubbles trapped in the glass. They can be caused by either impurities in the glass or an under heated furnace.
Shears – a scissor-like tool used to cut glass while in the molten state.
Silica - One of the essential ingredients used in making glass; a mineral, the most common form being sand from the seashore or inland beds.
Silica –Silver Sulphide – Used to produce a deep yellow glass stain.
Silicon dioxide - A mixture that is the main ingredient of glass. The most common form of silica used in glassmaking has always been sand.
Size - In glass working, the name applied to several glutinous materials, such as glue and resin, used to affix color or gold leaf.
Slump Glass (see “Bent Glass”)
Soda or Sode - Sodium carbonate. Soda (or alternatively potash) is commonly used as the alkali ingredient of glass. It serves as a flux to reduce the fusion point of the silica when the batch is melted.
Soda Glass or Soda Lime Glass - Soda glass (Venetian) contains soda instead of potash. It can be yellowish or brownish and is more malleable than lead glass. Most widely produced type of glass.
Stained Glass (or Flashed) - Glass that has been painted or sprayed with a colored stain and then fired in a muffle kiln to fuse to the surface to produce a consistent overall color to the surface. After firing, the pigment became a color and set into the glass surface, it was removed and the burned ash on the staining was cleaned and the color was polished into a high gloss. The stain can be cut through to reveal the under color and is easily scratched off. (See Needle Scratched)
Stangenglas (German, "pole glass") - A tall, narrow, cylindrical drinking vessel (hence the name "pole glass"), usually with a pedestal foot.
Stippling - The technique of tapping and drawing of small, fine lines on the surface of a glass object with a pointed tool, often with a diamond or tungsten-carbide tip. Each tap produces a mark or small line and the decoration is composed of many hundreds or thousands of marks. This technique was popular in the Netherlands in the 18th century and is also found on English glasses.
Sulphides - An internal decoration which imbedded porcelain-like figure within the glass; occasionally enameling on gold foil was also imbedded.
Tank - A large receptacle constructed in a furnace for melting the batch. Tanks replaced pots in larger glass factories in the 19th century.
Tiefschnitt (German, "deep cut") - See Intaglio.
Trail - A strand of glass, roughly circular in section, drawn out from a gather.
Temper - The process used to increase the strength of glass by reheating it after it’s formed and then rapidly cooling.
Threading - The process of spinning glass threads onto already shaped bodies while in the molten state.
Tin oxide - Metallic ingredient used to give milk glass its opaque, porcelain-like white appearance; also used to make the opaque white glaze covering on faience.
Transfer enamel - The process in which an enameled decoration is printed onto paper which is then applied to the glass body and fired on, burning off the paper and leaving the transferred print in place; this process eliminated the need for hand-decoration.
Translucent glass - Glass that allows only a portion of light to pass through, making objects seen through it appear unclear; opaline is in this category.
Transparent glass - Glass that allows light to pass through without diffusion, allowing objects to be seen through it clearly.
Transparent enamel - Enamel that allows light to pass through it.
Undercutting - The technique of decorating glass in high relief by cutting away part of the glass between the body of an object and its decoration (e.g., on a cage cup).
Underlay - Two-layer or multi-layer glass with the colored layer inside the blown piece, coated with a layer of clear glass. The concentrated colored glass is cut directly on the pipe. And then it’s overlaid with one or two layers of clear glass. Then it’s blown to the desired shape, often to a more open shape, that allows room for a pattern inside e.g., a bowl.
Uranium glass - Glass colored with uranium oxide. This brilliant yellow-green glass was first made in the 1830s and German steins did have uranium added to the glass mix. It is also called Vaseline Glass by some but this is a mistake if it refers to a German stein. It glows a vivid bright green under Ultra Violet light (black light). This is due to the Ultra Violet radiation exciting the outer electrons of the uranium atoms which as a result give off energy and which is seen by our eyes as a bright green glow. This is called fluorescence. The more intense the UV the brighter the green glow and the less that the original yellow coloring can be seen. Uranium glass also has a slight green glow in daylight due to the Ultra Violet component of daylight acting on it. This glow is paler due to the effect of the other components of white light also striking our eyes. See Vaseline Glass.
Vaseline Glass - Vaseline glass is American made pressed glass from the twentieth century which was colored with a small amount of uranium. The name was given for the greasy appearance and color of the glass. No German steins were made from vaseline glass. Vaseline glass has a yellow-green hue in daylight and fluoresces bright green under Ultra-Violet light (black light).
Venetian glass - A style of glass made in Venice from the 13th century to the present time.
Wheel engraving (also see Copper Wheel Engraving) - A process of decorating the surface of glass by the grinding action of a copper wheel, using disks of various sizes and materials (usually copper, but sometimes stone). An abrasive in a grease or slurry is applied to a wheel, as the engraver holds the object against the underside of the rotating wheel. The technique was used in Germany in the 17th century, and became the most common form of engraving in England from the 18th century
Williamite glass - A 17th-century English drinking vessel engraved with a toast, a symbol (an orange tree, for example), or a motto supporting King William III, or with his portrait. William III, who was the hereditary prince of Orange, came to the English throne in 16 89. His political opponents were the Jacobites; see Jacobite glass.
Yard-of-ale - A type of ale glass with a trumpet-shaped mouth, a long and narrow neck, and a small, globular body as a base. It could not stand on its own due to the round base and came with a wooden holder. It was so-called because they were often one yard (three feet) long, these objects contained about one pint and functioned like trick glasses. The yard-of-ale is an English form, which came into use in the 1680s and continued into the 19th century.
Zwischengoldglas (German, "gold between glass) - A type of decoration, produced in Bohemia and Austria in the 18th century, in which a design in gold or silver leaf is incorporated between two vessels that fit together precisely. Unlike Hellenistic and Roman gold glass, which is fused, Zwischengoldglas is bonded with cement.
I know I am missing terms and descriptions of cuts (see the four below) and would appreciate any help you can give. Please send to me at: email@example.com I wll add it to the next version.
· Flat and Hollow Cuttings
· Edge or Slice Cutting
· Miter Cutting
· Pillar Cutting
Following are some of the most common cut glass patterns used during the 18th and 19th centuries. However, because they have been repeated in the 20th century, the pattern alone is not a reliable guarantee of authenticity. You should also look for the color of the glass and for irregularities that show it's handmade.