Corning Museum of Glass

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.

The pontil, or punty, is a solid metal rod that is usually tipped with a wad of hot glass, then applied to the base of a vessel to hold it during manufacture. It often leaves an irregular or ring-shaped scar on the base when removed. This is called the “pontil mark.”

A monochrome segment of glass cut from a trail.

An iron or steel tube, usually four to five feet long, for blowing glass. Blowpipes have a mouthpiece at one end and are usually fitted at the other end with a metal ring that helps to retain the gather.

A long, thin rod used to gather molten glass.

(Noun) A mass of molten glass (sometimes called a gob) collected on the end of a blowpipe, pontil, or gathering iron; (verb) to collect molten glass on the end of a tool.

Any instrument used by glassworkers to develop and shape an object. Glassworkers’ tools include the blowpipe, pontil, gathering iron, jacks, shears, clapper, pallet, block, pincers, battledore, lipper, and crimper.

A mass of molten glass, usually small and freshly gathered from the furnace. In a team of glassworkers, the bit gatherer removes bits from the furnace, using a bit iron. Bits are also known as gobs.

(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.

The technique of forming an object by inflating a gather or gob of molten glass on the end of a blowpipe. Traditionally and in modern furnace working, 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. In flameworking, one end of the glass tube is heated and closed immediately, after which the worker blows into the other end and manipulates the hot glass.

The process of decorating glass by the use of gold leaf, gold paint, or gold dust. The gilding can be applied with size, or amalgamated with mercury. It is then usually attached to the glass by heat. Gold leaf can be picked up on a gather of hot glass.

The fluid glass produced by melting batch.

(French, “glass paste”) A material produced by grinding glass into a fine powder, adding a binder to create a paste, and adding a fluxing medium to facilitate melting. The paste is brushed or tamped into a mold, dried, and fused by firing. After annealing, the object is removed from the mold and finished.

Any crystalline inclusion present in glass. Stones consist of unmelted particles of batch, fragments of refractory material from the pot, or devitrification crystals. Stones of the first two varieties are generally irregular but rounded; those of the third variety are angular and well formed.

An enclosed structure for the production and application of heat. In glassmaking, furnaces are used for melting the batch, maintaining pots of glass in a molten state, and reheating partly formed objects at the glory hole.

A mass of molten glass, usually small and freshly gathered from the furnace. In a team of glassworkers, the bit gatherer removes bits from the furnace, using a bit iron. Bits are also known as gobs.

(1) A rounded, hollow vessel; (2) the uppermost part of a goblet, tazza, or wineglass.

The term applied to several types of Hellenistic and ancient Roman glass objects decorated with designs cut and/or engraved in gold leaf, which is sandwiched between two fused layers of glass. Hellenistic gold glass was made by sandwiching the decoration between two closely fitting cast, ground, and polished vessels, which were then fused. Many Roman gold glasses apparently were made by applying the gold leaf to the surface of an object, reheating it, and inflating a parison against the decorated surface.

The process of cutting into the surface of an annealed glass object either by holding it against a rotating copper wheel fed with an abrasive or by scratching it, usually with a diamond.

Smoothing the surface of an object when it is cold by holding it against a rotating wheel fed with a fine abrasive such as pumice or cerium oxide. Glass can also be polished with hand-held tools.

(from French paraison) A gather, on the end of a blowpipe, that is already partly inflated.

The technique of removing the surface of an object with a rotating wheel fed with an abrasive, or by some other means.

The generic name for a wide variety of techniques used to form glass in a mold.

The technique whereby glass is removed from the surface of an object by grinding it with rotating wheels made of stone, wood, and cork. The first stage of the process employs a stone wheel under a continuous stream of water. Later, wheels of fine-grained stone and wood, fed with various abrasives, are used to grind and polish the surface.

Deep red glass colored by the addition of gold chloride to the batch. The method of making gold ruby glass was perfected by Johann Kunckel (1637-1703) in Potsdam shortly before 1679.

The mixture of raw materials (often silica, soda or potash, and lime) that is melted in a pot or tank to make glass. Cullet, as well as minor ingredients such as colorants, can be added to the batch to help the melting process.

A variety of ribbon glass that includes canes composed of bands of gold foil laminated between two layers of colorless glass. Gold-band mosaic glass was made in parts of the Roman world in the first century B.C. and the first century A.D.

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 façon de Venise glass.

(1) A type of first-century A.D. Roman mosaic glass that consists of ribbonlike canes arranged in parallel rows or geometric patterns; (2) a type of vetro a reticello made in Venice and at other places where façon de Venise glass was produced.

A surface decorated with many small, adjoining pieces of varicolored materials, such as stone or glass.

Glass that is colored by (1) impurities in the basic ingredients in the batch or (2) techniques of coloring glass by one of three main processes: (a) using a dissolved metallic oxide to impart a color throughout, (b) forming a dispersion of some substance in a colloidal state, and (c) suspending particles of pigments to form opaque colors.

The removal of glass from the surface of an object by means of hand-held tools or sandblasting.

The application of a layer of glass over a layer of contrasting color. 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 produce cameo glass.

Inflating a parison of hot glass in a mold. The glass is forced against the inner surfaces of the mold and assumes its shape, together with any decoration that it bears.

A form 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 (sometimes known as full-size molds) are used to give the object its final form, with or without decoration. Dip molds consist of a single part and are usually shaped like beakers. Full-size molds usually have two or more parts and can be opened to extract the object. Nowadays, most molds are made of metal, but stone, wood, plaster, and earthenware molds were used in the past and are still occasionally employed today.

A type of bottle with a short, narrow neck and a globular body, which apparently was filled with water and thrown into flames to serve as a fire extinguisher. Aeolipiles are sometimes identified, probably incorrectly, as grenades.

The generic name for decorative windows made of pieces of colored glass fitted into cames and set in iron frames. Strictly speaking, the term is inaccurate because, in addition to glass colored by staining, glaziers used, and continue to use, glass colored throughout by metallic oxide, glass colored by flashing, and glass decorated with enamel.

The process of breaking away the edge of a glass object with a grozing iron or pliers in order to shape it.

Glass of extreme purity and with welldefined optical properties, which was originally created for making lenses and prisms.

A fire-clay pot used in the manufacture of optical glass. It is named after its inventor, Pierre Louis Guinand (1748-1824).

A fire-clay container in which batch is fused and kept molten. The glassworker gathers glass directly from the pot.