Check out some of the most interesting and unusual diamonds and coloured stones submitted to GIA’s laboratories in 2019.
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Knowledge of type allows gemmologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a laboratory for testing.
Read MoreModern gemmologists and diamantaires are faced with a broad spectrum of colour and clarity treatments ranging from the simple to the highly sophisticated.
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This article explores and identifies the changes that type IIa GE POL diamonds experience before and after HPHT annealing.
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Several diamonds were treated for the purposes of observation and report with a new laser technique which does not show the typical surface-reaching drill hole.
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Results from spectroscopic analyses of GE POL high-pressure high-temperature (HPHT) annealed nominally type IIa diamonds are presented, and these spectral characteristics are compared with those of untreated diamonds of similar appearance and type.
Read MoreGeneral Electric has developed a variety of high-temperature annealing techniques at different pressures for enhancing the optical properties of polycrystalline synthetic diamond films and single-crystal synthetic diamond.
Read MoreSynthetic moissanite is much closer to diamond in overall appearance and heft than any previous diamond imitation; this article reports on how to identify and characterise it.
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Exploration of a chart designed to give jewellers and gemmologists a practical guide to identifying synthetic diamonds as they enter the jewellery trade.
Read MoreThis report focuses on recent products from Yehuda/Diascience, Koss & Schecter Diamonds (Genesis II) and Clarity Enhanced Diamond House (a subsidiary of Goldman Oved Diamond Co.).
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