Imitation opal

Description

Any man-made stone designed to resemble the iridescence of a natural opal. The first imitation opal was made by Pierre Gilson in the 1960s and first marketed in 1974. Gilson stone, as well as most other synthetic opals, contain an underlying honeycomb pattern that can be through a microscope. Many synthetics, called opalite, are made from silica. Some have been made or coated with plastics (acrylic, latex spheres, polystyrene). Some imitation opals have also been made by dyeing silicified sandstone or cemented silica spheres together. One good opal imitation, Slocum stone, is made from laminated glass with embedded bits of metal foil.

Synonyms and Related Terms

Opalite; Gilson stone; Slocum stone

Authority

• Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Opal (accessed Oct. 12, 2005)

• Michael O'Donoghue and Louise Joyner, Identification of Gemstones, Butterworth-Heinemann, Oxford, 2003