John I. Koivula, Maha Tannous, December 1, 2000
The 1990s witnessed important developments in the commercial viability of gem-quality synthetic diamonds.
Read MoreKarl Schmetzer and Ulrich Henn, September 1, 1997
An investigation of the difference between synthetic opal and opal simulant.
Read MoreK. Schmetzer, H. A. Hänni, E. P. Jegge, and E-J. Schupp, June 1, 1992
The gemmological properties of a new ruby imitation, produced by dyeing natural colourless to pale-coloured corundum, are described.
Read MoreRobert C. Kammerling, John I. Koivula, December 1, 1991
White, pink and black nontransparent synthetic "cubic zirconia" is currently being manufactured in Russia and marketed primarily in cabochon and bead form.
Read MoreJohn I. Koivula and Robert C. Kammerling, March 1, 1989
A plastic imitation opal that shows true play-of-colour was advertised as "new" and offered for sale under the trade name "Opalite" at the Gem and Lapidary Dealers Association (GLDA) Tucson show in February 1988.
Read MoreRobert E. Kane, September 1, 1987
This article reports on a detailed gemmological examination of this new synthetic cat's-eye alexandrite.
Read MoreJohn I. Koivula and C. W. Fryer, March 1, 1984
The authors examine an unusual crystal in matrix.
Read MoreKurt Nassau, March 1, 1984
The author has uncovered many ancient references to the simulation or enhancement of gemstones.
Read MoreGeorge Bosshart, December 1, 1983
The properties of a novel gemmological imitation, cobalt glass.
Read MoreTh. Lind, K. Schmetzer, September 1, 1983
Two techniques for identifying natural, treated and synthetic turquoise are examined.
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