A decorative effect that causes the surface of the glass to resemble cracked ice. This is achieved by repeatedly plunging a parison of hot glass into cold water and withdrawing it quickly. The thermal shock creates fissures in the surface, and these impart a frosted appearance after the parison has been reheated to allow the forming process to continue.
(Italian) The technique of constructing an object, usually a vessel, by fusing two or more blown glass elements. The process, first practiced in the Islamic world in the Middle Ages, demands great precision because the edges of the adjoining elements must have precisely the same diameter.
A collective term for bubbles, metal and glass particles, and other foreign materials that have been added to the glass for decorative effects.
Any object embedded in the surface of a larger object.
(from Italian, “engraving”) A method of wheel engraving whereby the ornamentation is cut into the object and lies below the surface plane. The German name for this technique is Tiefschnitt.
(from Italian intarsio, “marquetry”) A type of glass developed by Frederick Carder (1863-1963) about 1920. A design of colored glass was applied to a parison of a different color, then flashed with a second parison of the same color as the first.
(French, “inserted”) The process of applying two layers of decoration, the first being covered with a skin of glass that serves as the surface for the second.
The rainbowlike 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.