Presents a group of corundum standards developed by GIA to improve the accuracy and efficiency of its laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) instruments.
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Purplish Pink Spinel from Tajikistan: Before and After Cutting
Read MoreThis article describes the first application of laser-induced breakdown spectroscopy (LIBS) to gemmology.
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Since 1996, large quantities of yellow to blue sapphires have been recovered from alluvial deposits derived from basaltic rocks in northern Madagascar.
Read MoreGreater amounts of colourless sapphire—promoted primarily as diamond substitutes, but also as natural gemstones—have been seen in the gem market during the past decade.
Read MoreMost Russian hydrothermal synthetic rubies and pink, orange, green, blue and violet sapphires—coloured by chromium and/or nickel—reveal diagnostic zigzag or mosaic-like growth structures associated with colour zoning.
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Gem-quality rubies and pink to purple sapphires are being recovered from the Luc Yen and Quy Chau mining regions of Vietnam.
Read MoreToday, only by combining different gemmological tests with years of practical experience, can a conclusive determination of the origin of a sapphire be made.
Read MoreThe authors determined that there are actually seven types of "yellow" sapphire on the market today, which differ in the cause of colour and the stability of the colour to light.
Read MoreAn important clue in identifying natural-coloured corundum is the presence of carbon dioxide fluid inclusions.
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