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.
Coated Pink Diamond — A Cautionary Tale
The Diamond Trading Company (DTC) Research Centre had the opportunity to examine a diamond that, on submission to a commercial gem laboratory, turned out to be a coated pink diamond.
Treated-Colour Pink-To-Red Diamonds from Lucent Diamonds Inc.
Using a multi-step process, Lucent Diamonds has developed a new treatment process for certain natural diamonds that creates colours from pink-purple to red to orangey brown.
Two Treated-Colour Synthetic Red Diamonds Seen in the Trade
Two dark brownish red faceted stones, recently submitted to the GIA Gem Trade Laboratory for standard origin-of-colour reports, were found to be treated synthetic diamonds.
Contribution to the Identification of Treated Coloured Diamonds: Diamonds with Peculiar Colour-Zoned Pavilions
Some treated yellow and blue-to-green diamonds show a peculiar colour zoning when viewed through the pavilion.
Detection of Treatment in Two Unusual Green Diamonds
A pair of sharp absorption bands in the near-infrared region, referred to as H1b and H1c, have been detected in one (and the H1b band in the other) of two green diamonds known to have been treated.
Serenity Coated Coloured Diamonds: Detection and Durability
Diamonds treated using the new Serenity Technologies coating technique for inducing various “fancy” colours are reported.
“Fluorescence Cage”: Visual Identification of HPHT-Treated Type I Diamonds
HPHT-treated type I diamonds of various colours may exhibit unusually intense fluorescence at the facet edges and junctions.