by Richard W. Hughes
A Fool's Guide to Color in Gems

Color types such as "pigeon's blood," "Paraíba" and "cobalt blue" have become wildly popular in the gem trade. But there is a vast difference between coining such terms and applying them in a way that is both consistent and logical. Richard Hughes casts a critical eye at the subject.

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by Lotus Gemology
Gem Testing Labs • Tips on Choosing a Colored Gem Testing Lab • Lotus Gemology

How does one go about choosing a good gem testing lab? The gemologists at Lotus Gemology provide the following guide to help customers make the best decisions when choosing a good gem testing lab.

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by E. Billie Hughes and Wim Vertriest
Burmese Ruby: Low-Temperature Heat Treatment Experiments

Detection of heat treatment below 1200°C in ruby and sapphire can present challenges to gemologists. In this study, the authors heated Burmese ruby samples and detailed the features that help in the detection of heat treatment.

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by Richard W. Hughes
Treatment Disclosure • Notes from the Eastern Front

A truth that's told with bad intent, beats all the lies you can invent.

—William Blake [1757–1827], Proverbs, Line 95

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by Richard W. Hughes
Oiled Spinel • A Shocking Revelation

When a red spinel and a tanzanite were submitted for testing, oil was found in the fissures. Removal of the oil resulted in a startling deterioration in clarity.

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by E. Billie Hughes
Curved banding in flame fusion synthetic sapphire.

Short-wave fluorescent illumination provides a useful tool to spot curved banding in flame-fusion synthetic sapphire.

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by E. Billie Hughes
Yellow sapphire before and after fade test

Some yellow sapphires contain unstable color centers. The following discussion outlines case studies of stones that faded after testing in the lab, and how color may be restored.

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by E. Billie Hughes
Apatite in garnet

Blue apatite crystals in garnet.

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by E. Billie Hughes
Apatite crystal in sapphire

An apatite crystal appears to float, suspended over a rutile silk cloud in a star sapphire.

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by E. Billie Hughes

Oil treatment has a significant impact on the appearance of an apatite.

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