- Frederick Norman Pryce
- and Michael Vickers
Glass (ὕαλος (also 'rock crystal'), vitrum). The art of producing a vitreous surface on stone, powdered quartz (faience), or clay was known in pre-dynastic Egypt and passed to Crete during the second millennium bce. Glazed objects are common on Greek sites of the Archaic period, some of them Egyptian imports, others probably made locally. In Hellenistic and Roman times Egypt and Asia Minor were centres of fabrication of glazed wares, which often imitated bronze.
Objects composed entirely of glass paste begin to appear in Egypt about 1500 bce, when two allied processes seem to have been in use: modelling molten glass about a core of sand, and pressing it into an open mould. The chief Mycenaean glass is dark blue imitating lapis lazuli, used for beads, inlays, and architectural ornaments. In the 6th cent. small vases made by the sand-core process became known in Greece; they have opaque blue, brown, or white bodies and a marbled effect was produced on their surface by means of a comb or spike. In the Hellenistic period mould-made bowls come into fashion; these were produced mainly in Egypt. Here the tradition of opaque polychrome glass was continued into Roman times with millefiori bowls, in which marbled and other polychrome patterns were formed by fusing glass canes of various colours and pressing them into moulds. In the same tradition are the vessels in two layers carved in imitation of hard-stone cameos: the Portland vase in London is the best-known example.
The invention of glass-blowing in the 1st cent. bce (probably in Syria) wrought great changes in the glass industry, which, hitherto limited to relatively expensive surrogates for luxury goods, now became capable of cheap mass-production, but even then the most highly valued glass was ‘colourless and transparent, as closely as possible resembling rock crystal’ (Plin.HN 36. 198). Glass was used in the home and for funerary furniture. Glass-works have been located in many provinces, but in the later western empire, Belgic Gaul and Germany had taken the place of Italy and southern Gaul. Even Britain had some glass-works. The vessels, even when plain, show much variety of form, and there are several styles of decoration—tooling or applying relief ornament to the surface when warm, cutting or engraving or painting when cold. Window glass, made by a primitive process of rolling, was known at Pompeii, and later became common; in the later empire also begins the use of glass for mirrors. Gemstones were imitated in glass paste at all periods from the 7th cent. bce onwards (see gems). Burning-glasses were used, and these may conceivably have been used as magnifying glasses by gem engravers; spectacles were unknown.
- Faience: V. Webb, Archaic Greek Faience (1978).
- Glazed pottery: H. Gabelmann, Jahrbuch des [kaiserlich] deutschen archäologischen Instituts 1974, 89.
- P. Fossing, Glass Before Glass-blowing (1940).
- D. F. Grose, in W. D. Kingery (ed.), High Technology Ceramics (1986).
- M. Newby and K. S. Painter, Roman Glass: Two Centuries of Art and Invention (1991).
- M. VickersJournal of Roman Archaeology 1996.
- A. von Saldern, Antikes Glas (2004).