An Era of Sweeping Change in Diamond and Colored Stone Production Markets
The diamond, colored stone, and pearl businesses have witnessed unprecedented change since the turn of the 21st century.
From Single Source to Global Free Market: The Transformation of the Cultured Pearl Industry
Over the past 15 years a combination of market forces, environmental events, and scientific research has radically changed the cultured pearl industry.
Sapphire Rush Near Ambatondrazaka, Madagascar (英語)
A newly found deposit of sapphire in Madagascar is explored.
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.
“Paraíba”-Type Copper-Bearing Tourmaline from Brazil, Nigeria, and Mozambique: Chemical Fingerprinting By LA-ICP-MS
Gem-quality bright blue to green “Paraíba”-type Cu-bearing tourmaline is now known from deposits in Africa (Nigeria and Mozambique), in addition to three commercial localities in Brazil (in Paraíba and Rio Grande do Norte States).
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.
The Santa Terezinha De Goias Emerald Deposit
The author has uncovered many ancient references to the simulation or enhancement of gemstones.
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.
Abstracts; Spring 1994
This article, from the Spring 1994 issue of Gems & Gemology, is a compilation of abstracts of important gemology-related articles published outside of Gems & Gemology.
The Anahí Ametrine Mine, Bolivia
The Anahí mine, Bolivia, has produced large amounts of amethyst, citrine, and amethyst-citrine for the gem market.
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.
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.
Glassy Melt Inclusions in Sapphires from Montana
Two-phase inclusions are investigated in alluvial sapphires from deposits in Montana.
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.
Imitation Rubellite Boulders
Specimens presented as rubellite tourmaline rough are found to be resin imitations with lead inserts.
Mixing of Natural Diamonds with HPHT Synthetic Melee
Screening reveals a surprise within a batch of synthetic diamond melee.
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.
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.
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