Negative Crystals in Sapphires

Sapphires from Baw Mar host multiphase inclusions in appealing patterns.

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Quarterly Crystal:Mystery in Topaz

A topaz hosting a group of inclusions is examined in the Carlsbad lab.

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Imitation Cat’s-Eye Pen “Pearls”

Imitation pearls show kaleidoscopic colors with illumination.

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Flashes and Flames in Ethiopian Opal (英語)

Chatoyancy, rarely seen in play-of-color opal, is observed in Ethiopian material.

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Ametrine Optical Dishes: Windows into the Effects of Crystal Structure

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