by Thanong Leelawatanasuk, Wilawan Atichat, Visut Pisutha-Arnond, Pornsawat Wattanakul, Papawarin Ounorn, Wimon Manorotkul & Richard W. Hughes
Cobalt-Doped Glass-Filled Sapphires  |  An Update  |  Lotus Gemology

The history of glass-infilling in blue sapphire, along with a description of the latest treatment generation developed in Chanthaburi, Thailand.

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by John I. Koivula & Richard W. Hughes
Living in the Dark Ages  |  The Fiber-Optic Light

The role of fiber-optic lighting in gemological microscopy.

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by Richard W. Hughes
Ownership of Words  |  An Essay on Padparadscha Sapphire

The definition of padparadscha sapphire, from early to modern times.

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by John I. Koivula & Richard W. Hughes
Following the Silk Road  |  Rutile in Corundum

A discussion of rutile silk in corundum and its use in detecting artificial heat treatment. Careful examination of these "silk" inclusions can provide vital clues to unmask heated gems.

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by Richard W. Hughes
Proletarian Gemology  |  The Blue Filter

Introducing the blue filter as a gemological tool to separate natural and Verneuil synthetic yellow sapphires.

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