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Sapphire
The name “sapphire” can also apply to any corundum that’s not ruby red, another corundum variety.
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Tools
Research
Madagascar Sapphire: Low-Temperature Heat Treatment Experiments
Shows how the color of Madagascar sapphire is lightened with heating to relatively low temperatures below 1350°C.
U-Pb Ages of Zircon Inclusions in Sapphires from Ratnapura and Balangoda (Sri Lanka) and Implications for Geographic Origin
Establishes a metamorphic origin for sapphire samples from these deposits, supported by their trace-element composition and inclusion characterization, including the age dating of zircon inclusions.
Montana Yogo Sapphires’ Unique Gemology
A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.
Microscopic Observations of Blue Sapphires Treated with Heat and Pressure
In recent months, sapphires treated under heat and pressure have been documented in the trade.
Large Pargasite Inclusion in Kashmir Sapphire
Unusually large prismatic pargasite inclusions observed in a Kashmir sapphire submitted to the Carlsbad lab for origin determination.
Gemstone Guidebook Project
A project coordinated by GIA and the NGO Pact provides a valuable educational tool to women miners in Tanzania.
Twelve-Rayed Star Sapphire from Thailand
A black star sapphire produced from eastern Thailand, showing both golden and silver rays, is studied at GIA’s Bangkok lab.
Update on Trace-Element Chemical Characteristics of Golden Sheen Sapphire
Gemological Characterization of Sapphires from Yogo Gulch, Montana
A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.
Features of Synthetic Diamonds
Presents a visual guide to the growth processes and major gemological spectroscopic features of synthetic diamonds.
Characterization of Blue Sapphires from the Mogok Stone Tract, Mandalay Region, Burma (Myanmar)
The Mogok Stone Tract of central Myanmar (Burma) is one of the world’s most famed sources of colored stones, particularly ruby, sapphire, and spinel.
