Diffusion-Induced Blue Spinel-Like Layer on Natural Sapphire
Three natural sapphires exhibiting a surface layer of gahnite are studied at the GGTL laboratory.
Gold-Plated Gold
The application of plating is detected on gold jewelry pieces in the Carlsbad laboratory.
Emeralds of the Panjshir Valley, Afghanistan
With the withdrawal of Soviet troops from Afghanistan, villagers in the Panjshir Valley are turning their attention to the emerald riches of the nearby Hindu Kush Mountains.
The Anahí Ametrine Mine, Bolivia
The Anahí mine, Bolivia, has produced large amounts of amethyst, citrine, and amethyst-citrine for the gem market.
Gray-To-Blue-To-Violet Hydrogen-Rich Diamonds from the Argyle Mine, Australia
The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds colored gray to blue to violet.
Aquamarine from the Thuong Xuan District, Thanh Hoa Province, Vietnam
Vietnamese aquamarine is notable for its attractive color and well-formed crystals.
Characterization of Colorless Coated Cubic Zirconia (Diamantine)
Over the past several years, diamond simulants have entered the market that consisted of colorless cubic zirconia reportedly coated with a thin layer (e.g., represented to be 30–50 nm) of nanocrystalline diamond particles embedded in a matrix.
An Opal-Calcite Composite
Gem Testing lab in Jaipur, India recently examined a white-brown, translucent to opaque oval cabochon that turned out to be a composite featuring an unusual combination of gem materials.
Winter 2011 G&G Lab Notes
This section, from the Winter 2011 issue of Gems & Gemology, is a compilation of interesting finds from GIA’s laboratories.
Imitation Rubellite Boulders
Specimens presented as rubellite tourmaline rough are found to be resin imitations with lead inserts.
D-Color Natural IIa Diamond with Walstromite Inclusion
A diamond is proven to have a superdeep origin through an inclusion of CaSiO3-walstromite.
Strong Fluorescence in B-Jade Impregnated with Wax
A bangle is an example of the misconception that B jade is only impregnated by resin, when in fact wax-impregnated jadeite is also considered B-jade.
HPHT-Processed CVD Laboratory-Grown Diamonds with Low Color Grades
The Antwerp lab examines CVD laboratory-grown diamonds where HPHT processing resulted in relatively low color grades.
Chrysoprase and Prase Opal from Haneti, Central Tanzania
Commercial quantities of gem-quality chrysoprase and green prase opal (nickel-bearing chalcedony and common opal, respectively) have been recovered from altered serpentinite deposits near Haneti, Tanzania.
Cutting Diffraction Gratings to Improve Dispersion (“Fire”) in Diamonds
A new microlithography process developed to create high-resolution diffraction grating patterns on portions of certain facets can improve the dispersion of light and thus the amount of “fire” in a 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 characterize it.
Sapphire Chart Article: Suggested Reading on Sapphires and Their Inclusions
Suggested Reading on Sapphires and their Inclusions
Suggested Reading on Emeralds and their Inclusions
Suggested Reading on Emeralds and their Inclusions
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