Gem News International Gems & Gemology, Winter 1991, Volume 27, No. 4

Winter 1991 Gem News International

            Botswana Expands into Diamond Manufacturing
            Large Chinese Diamond
            Diamond Center Planned for China
            Data Suggest Strong, Changing U.S. Diamond Market
            Diamond Factory to Open in Dubai
            G.E. Synthesizes Large Carbon-13 Diamonds
            Guinea's Aredor Produces another Large Diamond
            Indonesian Production on Line
            "Nickel Thermometer" for Diamond Exploration
            New "Royal" Diamond Cuts
Colored Stones
            Hairy Insect in Amber
            Czechoslovakian Conference Yields Valuable Information
            Novel Chrysoberyl "Cross" Cat's-Eye
            Attractive Tanzanian Diopside
            Fine Emerald/Green Beryl from Nigeria
            New Production of Demantoid Garnets from Russia
            Tanzanian Yellow Grossular Garnets
            Large Tsavorite Garnet from Tanzania
            "Recycled" Ivory
            More on Peruvian Opal
            Antique Portrait Ring
            More Synthetics Sold as Natural Ruby in Vietnam
            Update from Sri Lanka
            Sunstone/Iolite Mixture
            Update on Tanzanite Mining
            Bicolored Tourmaline with Unusual Color Effect
Synthetics and Simulants
            New Laser Crystals with Gem Potential
            Novel Synthetic Star Sapphire
            More on Opticon as a Fracture Filler
            Filled Cavernous Emerald Crystal
            Filled Synthetic Emerald in Parcel from Swat
            Deceptive Color Coating of Sapphires in Sri Lanka
            More on Paraiba Tourmaline Simulants
Instrumentation and New Techniques
            Distinguishing Diffusion Treatment from Surface Coating
            New Setting Method Challenges Diamond Testers
            Jewelry Imaging/Teleconferencing System Introduced
            Tweezer Improvement
            Southeast Asia Gemmological Conference
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