Gem treatment disclosure and U.S. law
In recent years, the obligation to fully disclose all gem treatments has changed from a mere ethical responsibility to a legal one.
Celebrating 75 Years of Gems & Gemology
Gems & Gemology, the professional quarterly of GIA, debuted in 1934
A New Method for Imitating Asterism
Several gems were recently examined that showed stars with an unnatural appearance or an unusual number of rays.
The Early History of Gemstone Treatments
The author has uncovered many ancient references to the simulation or enhancement of gemstones.
The author reviews the nature of this material and some of the forms into which it has been fashioned, as well as means of identifying hornbill ivory from other ivories and from imitations.
Gemmological Properties of Near-Colourless Synthetic Diamonds
Examination of 51 colourless to near-colourless synthetic diamonds from all known sources of production confirms that they can be distinguished from similar-appearing natural diamonds on the basis of their gemmological properties.
Mildly Radioactive Rhinestones and Synthetic Spinel-And-Glass Triplets | Gems & Gemmology
Low levels of radioactivity were found in some greenish yellow to yellow-green (peridot-like) synthetic spinel-and-glass triplets, mirror-backed glass rhinestone chatons and fully fashioned glass rhinestones.
'Cobalt-Blue' Gem Spinels
Similarities between natural spinels - with intense blue colour - and synthetic material, have led to difficulties in the recognition of the natural stones by traditional methods.
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.
Dyed Natural Corundum as a Ruby Imitation
The gemmological properties of a new ruby imitation, produced by dyeing natural colourless to pale-coloured corundum, are described.