The “Type” Classification System of Diamonds and Its Importance in Gemmology
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.
A History of Diamond Treatments
Modern gemmologists and diamantaires are faced with a broad spectrum of colour and clarity treatments ranging from the simple to the highly sophisticated.
GE POL Diamonds: Before and After
This article explores and identifies the changes that type IIa GE POL diamonds experience before and after HPHT annealing.
A New Lasering Technique for Diamond
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.
Spectroscopic Evidence of GE POL HPHT-Treated Natural Type IIA Diamonds
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.
Clues to the Process Used by General Electric to Enhance the GE POL Diamonds
General 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.
Synthetic Moissanite: A New Diamond Substitute
Synthetic 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.
A Chart for the Separation of Natural and Synthetic Diamonds
Exploration of a chart designed to give jewellers and gemmologists a practical guide to identifying synthetic diamonds as they enter the jewellery trade.
An Update on Filled Diamonds: Identification and Durability
This 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.).
The Characteristics and Identification of Filled Diamonds
This article reports on the study of six diamonds, both before and after a filling treatment, and the examination of 12 additional filled stones.