The New York lab encountered another large HPHT-treated diamond that showed stronger pink colouration.
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Zircon clusters and other inclusions help to create an unusual vivid purple-pink morganite specimen.
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Advances in CVD growth technology have resulted in crystals that yield well-proportioned round brilliant cuts.
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Recently, an unusual 0.94 ct Fancy yellow-brown emerald was submitted to GIA for a synthetic diamond grading report. It contained a cloud of black needle-like inclusions occurring along a plane and showed weak green transmission with fibre-optic illumination.
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Deep blue fluorescence in a CVD synthetic diamond mimics patterns found in natural specimens.
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A fingerprint pattern, possibly left by human skin oils during the assembly process, is observed in natural turquoise beads.
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The first documented UV-reactive chemical treatment to make opal appear tenebrescent.
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Microradiography reveals wire fillings within a “pearl” created from two separate specimens.
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For the first time, GIA's laboratory has examined tanzanite colour-coated with titanium.
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The stone owes all of its green colour to these shallow radiation stains.
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