Defining Glass Terms - Part I

courtesy of Charles Upton
Issue #83 - March 1980

ALPINE: is a decoration used on the Caprice pattern. Portions of the pattern were painted with an etching ground and the article was then immersed into a Hydrofluoric acid solution, to etch, or frost, the unpainted surfaces.

AMBER: Cambridge Amber is of the lustrous sparkling type of Amber. There are not many others having this same quality in the same degree.

AMETHYST: is a medium purple.

APPLIED STEM (stuck shank): stem of a vessel made from a separate gather of metal and welded to the bowl or body.

ARSENIC: Correctly Arsenic Trioxide. Chemical formula is As2O3. It occurs associated with copper in its ores and is a by-product of the copper industry. It is found in the U.S., Canada, Mexico and the Belgium Congo. It is used as a clarifying agent in the glass industry.

BARILLA: soda or salts from calcined plants native to Spain.

BITUMEN (bih TYOO mun): is a name given to a number of mineral substances which are composed chiefly of hydrogen and carbon. Forms of bitumen include mineral pitch or mineral tar and asphalt. Bitumen is used in the solution which is used in the coating of glassware to protect it during the etching process.

BLACK OXIDE OF COPPER: is made from metallic copper by heating in the presence of air. Chemical formula is CuO. Copper is found in many countries, very largely in the U.S. Black oxide of Copper is used to produce a blue green glass.

BLOCK: wooden dipper-like devise cut out on one side and used in the early stages of manipulation to give symmetrical form to a large parison.

BORAX: is made from colemonite or rasorite, both natural products and also occurs in the natural waters of certain California lakes from which it is separated from other salts present. Chemical formula is Na2B4OO7. It is also found in Nevada. It is used as a flux in glassmaking and to produce glass with heat resisting qualities.

CALCER: calker or caulker - the oven or the furnace in which the frit was made or the silica was burnt.

CALCIUM SULPHIDE: is made from metallic dadmium which occurs associated with zinc ores. Chemical formula is CdS. It occurs in Canada and the U.S. Cadmium Sulphide is used with selenium in the production of red glass.

COBALT OXIDE: is mined in the impure state in Canada and the Belgium Congo. Purified in Canada, Belgium and Germany. It is used to produce blue glass.

CROWN TUSCAN: is a new pinkish-ivory translucent glass, somewhat resembling very high-grade china. This glass takes a very high fire polish and the colorings in each piece vary slightly in an interesting manner.

CROWN TUSCAN D/1001: This pattern is the result of inlaying Crown Tuscan with 22-karat gold, burnt and burnished. The first process in this work is to put on a deep plate etching, the etching is then filled with gold and after the surface is carefully cleaned off so that only the gold down in the etching is left on the glass, it is then burnt. All of this gold work is of the very best quality and if properly used there is no danger of the gold wearing off.

CARMEN #3011: This stemware line has a nude figure stem in crystal, bowl of a very nice ruby red. This ruby is made in such a way that it does not give the appearance of being amberish, nor does it have light red spots in it.

CERIUM HYDRATE: The metal occurs in monazite sand from which it is separated and the salt prepared. Chemical formula is Ce(OH)2. Monazite sand is found in India, Brazil and North Carolina.

CHAIN: heavy threads of glass tooled into a chain. These chains were made by workmen presumably on their own time for their friends or family. They were made in various widths, lengths and shapes. Some were made from one color of glass while others were made from almost every color that was produced by the Cambridge Glass Company.

CRYSTAL: natural rock crystal, fine colorless or clear glass.

DRAWN STEM: stem of a vessel made by pulling out and manipulating metal from the base of the body, called also straw stem or hollow stem. This was found on several of the Champagne or Burgundy stems.

ETCHING GROUND: is a composition of wax, gum resin and bitumen used in the etching of glassware and other metals. The etching ground is applied to the glass by several methods. The areas not protected by this etching ground are etched, or frosted when immersed into a Hydrofluoric acid solution.

EYE (Occhio): center of the grate in the seize, the hottest part of the furnace.

FELDSPAR: is a natural rock, which is used in glass for its alumina and potash content. While it is mined in many parts of the United States and Canada, Tennessee supplies the larger amounts of this material for the glass industry.

FIRE POLISHING: reheating of finished vessels to obliterate marks left by tools or molds and to obtain a smooth even surface. This method was used widely at the Cambridge Glass factory.

FLINT GLASS: (1) metal made with the silica of flints reduced to a powder or made friable by calcination. (2) lead glass, metal made with oxide of lead as the flux and sand as the silica.

FLUX: an alkaline or metallic substance, such as potash and carbonate of soda and oxide of lead, added to the batch to fuse the silica.

FLY: the breaking into pieces of a vessel, caused by too sudden cooling.

FOREST GREEN: articles made in this color have a cool green shade, reminding one of springtime forests, from which the color was named.

FOUND: the time taken for melting the batch, from the charge until the molten metal is ready to work.

FREE-BLOWN GLASS: glass formed by blowing and manipulation with the tools of the craft without the aid of molds. This technique was used quite extensively by the Cambridge Glass Company.

FRIGGER: an experimental or apprentice piece.

FRIT: partially fused ingredients for the metal, formed in the calcar and kept on hand for melting; also synonymous with batch.

FULL-SIZE PIECE MOLD: mold composed of two or more pieces and the approximate size of the finished article.

GADROON OR GADROONING: molded deep rounded flutes or ribbing impressed on a second short layer of glass which was formed by attaching a pearl or purl to the end of a parison and pulled up over it. The name of a Cambridge pattern, pattern #3500 which resembles the above type process but was done in the mold itself.

GAFFER: master blower, head of a shop.

GATHER: the blob of molten metal secured on the end of a blowpipe.

GATHERER: assistant to the gaffer who makes the gather on the blowpipe

GLASS GALL: (sandever): porous scum formed on the surface of the melting batch by salts in the alkalis and having no affinity for silica, or by wrong proportions of ingredients.

GLASSMAKERS' SOAP: black oxide or manganese which added to the batch in the proper proportions neutralizes the natural color of the metal.

GLASS POTS: see melting pots.

GLORY HOLE: small furnace used instead of the boccas or working holes for the frequent reheatings necessary during the processes of manipulation and for fire polishing.

GREEN GLASS: glass in its natural color, neither rendered colorless nor artificially colored; generally made from coarser and less pure materials than those used for fine wares, principal alkaline base, soda or potash, second base, usually some form of lime; also called bottle glass.

GUILLOCHE: see Chain

GUM RESIN: is a group of vegetable substances which are obtained from the leaves, bark and roots of plants. Balsam is of this group and is used in the solution, which is used in the coating of glassware, to protect it during the etching process.

HAND-BLOWN: see free-blown.

HEAT RESISTANCE: Our Salad Plates, Cups & Saucers, Vegetable Dishes and other pieces, supposed to stand heat, are annealed very carefully and thoroughly so that they will stand the ordinary usage they are intended for.