Glass made in the rural glasshouses of central and northern Europe in the late Middle Ages and the early modern period. Most forest glass was fluxed with potash derived from the wood with which the furnaces were fueled. It is green because of iron impurities in the sand from which it was made. The German term for forest glass is Waldglas.
(German, “wart beaker”) A heavy glass tumbler made of forest glass and decorated with prunts. It was produced in Germany in the 16th and 17th centuries.
A defective object discarded during manufacture. Wasters are routinely recycled as cullet.
A pitcher with matching tumblers, sometimes with a matching tray.
Changes on the surface of glass caused by chemical reaction with the environment. Weathering usually involves the leaching of alkali from the glass by water, leaving behind siliceous weathering products that are often laminar.
The result of 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 that may feel damp or oily. Crizzling can be slowed or perhaps even halted, but it cannot at present be reversed. Crizzled glass is sometimes described as “sick” or “weeping.”
A process of decorating the surface of glass by the grinding action of a wheel, using disks of various sizes and materials (usually copper, but sometimes stone), and an abrasive in a grease or slurry applied to a wheel, as the engraver holds the object against the underside of the rotating wheel. See also Cutting and Copper-wheel engraving.
The English term for an object made by a glassworker on his own time. Most friggers were made from the molten glass that remained in the pot at the end of the day. Such glass was considered to be a worker’s perquisite. American glassworkers referred to friggers as “end-of-day” objects. They are also known as whimsies.
A late 17th- and 18th-century English drinking vessel engraved with a toast, a symbol (an orange tree, for example), or a motto supporting William of Orange (King William III, r. 1689-1702), or with his portrait. William III was a Protestant, and his political opponents were the Roman Catholic Jacobites. Many Williamite glasses have been shown to be late 19th century fakes, some perhaps executed by the Bohemian glass engraver Franz Tieze (1842-1932).
A decanter with matching wineglasses, sometimes with a matching tray.
A type of goblet with the stem in the form of vertical, winglike flanges composed of trails arranged in a complex design that may include dragons, sea horses, and other creatures. The German term for a winged goblet is Flügelglas.
A glass globe intended to be hung in a prominent place to ward off the evil eye.
A pattern of spiraling vertical ribs made by inflating the parison in a dip mold with vertical ribs, withdrawing it, and twisting it before continuing to inflate. The pattern is also described as wrythen.