Glossary

annealing

The gradual cooling down of a finished vessel or object. This process took place in a small subsidiary part of the furnace or in an annealing oven.

blowing spirals

Swirling streaks visible on the surface of the vessel resulting from the glassblower’s rotary movements of the blowpipe during the shaping of the object.

blowpipe

A metal tube, usually iron, used to blow glass.

cast vessel

A glass vessel formed in a mold.

chunk

A piece of raw glass destined for secondary production.

coil

A thick thread of glass, usually circular or oval in section, used as part of a vessel (e.g., a handle or rim) or as embellishment.

composite mosaic

Thin sections or lengths of one or more mosaic canes fused together and embedded in a ground color to create a geometric or floral pattern.

core-forming

The construction of a vessel by forming around a rigid core that was subsequently scraped out. A core of organic and inorganic materials is made on the end of a metal rod. The rod is rolled on crushed glass and then inserted in the kiln until the glass melts and covers the core. The neck and rim of the vessel are formed with tools, and handles and bases are added. The decoration is usually made by winding threads of colored glass.

corrosion

See weathering

dip mold–blowing

The technique of partially forming a vessel by blowing into an intaglio or mold. The vessel then acquires its finished dimensions through free-blowing, during which the original mold-made decoration is blunted or altered.

fire-polishing

The smoothing of a vessel or object through exposure to direct heat by inserting it momentarily into the glass furnace. This technique was used particularly often to finish the rims of vessels.

former mold

A convex mold of ceramic, plaster, or metal over which a disk of glass was sagged to acquire the desired shape.

free-blowing

The technique of forming an object by blowing air through a mass of hot glass using a blowpipe.

gather

See paraison

groze

To give shape to a piece of glass by trimming or chipping its circumference.

marver

A marver is a flat, level surface of stone, usually marble, atop which glass objects are rolled in various stages of secondary production. The purposes of the rolling, or marvering, can be to achieve the vessel’s final form, to smooth the surface, or to incorporate inlays or attached elements.

moil

The upper segment of the paraison; i.e., the portion at or around the end of the blowpipe, which in the final stage of forming is cracked off as excess.

mold-blowing

The technique of forming a vessel by blowing into a concave or specially shaped mold. The vessel is completed by the free-blowing of its rim and handles.

mosaic cane

An elongated mass of glass, usually circular in section, consisting of strands of different colors, thin sections of which were used in the production of mosaic vessels.

mosaic glass

Glass created from prepared elements of colored glass. The elements (rods, mosaic cane sections, rosettes, bands) are placed in a mold and fused.

paraison

The bubble of glass at the end of the blowpipe in the free-blowing technique, from which the glass vessel is formed. Also known as the gather.

pinprick bubbles

Very small bubbles trapped in the mass of glass during the process of fusion.

pontil mark

The ring-shaped trace of the blowpipe, normally on the bottom of blown vessels and on Byzantine bracelets, caused by the process of cracking off the glass product from the blowpipe or rod after the forming is complete. The mark may have the form of either a pontil scar (concave) or an excess (convex).

pontil scar

See pontil mark

raw glass

Unused glass destined for secondary production.

rod-forming

The construction of a glass object around a metal mandrel.

rotary pressing

The technique of forming a vessel on a potter’s wheel. The viscous glass is pressed down with a plunger, either directly on the rotating wheel or in a concave or convex mold.

sagging

The shaping of a vessel by reheating a glass disk or blank, which is allowed to flow by gravity into a concave mold or over a convex former mold.

slumping

See sagging

thread

A delicate filament of glass, formed by drawing or pulling, used as decoration on beads, pendants, and vessels made with the core-forming and free-blowing techniques.

trail

See thread

weathering

Alteration in the glass, first on its surface and then below the surface, as a result of environmental factors. It is due to the loss of alkaline ions and the creation of a siliceous layer on the surface, and is influenced by the composition of the glass. Weathering is a general term that includes the following specific types: discoloration, loss of vitreous nature, pitting, milky weathering, crusting, dulling, iridescence, crazing or crizzling, plowing, cracking or fracturing, sugaring, and lamination.