by E. Billie Hughes and Rosey Perkins
Madagascar Sapphire: Low-Temperature Heat Treatment Experiments

Madagascar has become one of the world’s top sources of fine blue sapphire in recent times. In addition to beautiful untreated material, increasing numbers of treated stones have appeared in the market. Some have been heated to relatively low temperatures, below 1350°C, to lighten their color. To help separate unheated and heated Madagascar sapphire, the authors performed experiments to document the changes they undergo with low-temperature heat treatment in air, which is an oxidizing atmosphere.

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by Richard W. Hughes, Wimon Manorotkul & E. Billie Hughes
Madagascar Ruby & Sapphire | Ruby & Sapphire: A Gemologist's Guide

This excerpt from Ruby & Sapphire: A Gemologist's Guide (2017) details the ruby and sapphire deposits of Madagascar. Since the mid-1990s, Madagascar has become one of the world's most important sources.

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by E. Billie Hughes, John I. Koivula, Wimon Manorotkul, Nathan Renfro and Richard W. Hughes
Inclusions in Spinel • An Exercise in Aesthetics

To the jeweler, spinel is famous for its vivid colors. But for the gemologist, this gem is unlike any other. Its extreme hardness allows a fine polish. Couple this with single refraction, which eliminates the image blurring found in most other gems, and a varied landscape of inclusion subjects, and the result is an unparalleled canvas of delight for the photomicrographic artist.

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by [see below for authors]
Sapphire Squeeze • Corundums treated with high temperatures and low pressure

27 February 2019: Sapphires heated with high temperatures and low pressures (~1kbar) first entered the market in 2009, becoming more common since 2016. This article examines the process in detail and looks at the question of whether a separate disclosure is needed for the treatment.

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by Richard W. Hughes, with E. Billie Hughes & Wimon Manorotkul
Colored Stone Grading • A Heretic's Guide

Developing a comprehensive colored stone grading system has been the dream of gemologists since the late 1970's, but despite a number of valient attempts, we are no closer to the goal today than we were four decades ago. This article examines the various problems of colored stone grading, explaining why the challenges are at least an order of magnitude greater than the grading of diamonds.

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by E. Billie Hughes
GemmoRaman-532 • Instrument Review • Lotus Gemology

The difference between a synthetic, treated, or untreated natural gemstone could mean a difference of thousands, even millions of dollars. Thus, it is no wonder that laboratories are becoming more in demand than ever. With treatments become increasingly sophisticated, gemologists and traders search for new tools to help identify stones.

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by Richard W. Hughes
Red Rain • Mozambique Ruby

Is the Mozambique stone the bejesus of bird's blood? Lotus Gemology's resident ruby wallah, Richard Hughes, weighs in on the state of the market and how Mozambique stacks up to historical heavyweights like Burma and Thailand/Cambodia.

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by E. Billie Hughes, Chawalit Chankhantha, Andreas Burkhardt, Wimon Manorotkul & Richard W. Hughes
Padparadscha or Pretender • An Unusual Pink-Orange Sapphire

An orangish pink “padparadscha” sapphire was submitted for testing at Lotus Gemology’s Bangkok laboratory. Testing showed a number of conflicting features that suggested the gem was a cleverly treated synthetic pink sapphire designed to imitate natural padparadscha.

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by Lotus Gemology
Gem Inclusion Pairs • Hyperion Siamese Twins

Why should Hugh Hefner be the only one to enjoy twins? This special Hyperion Inclusion Gallery features images from the Lotus Gemology Hyperion Inclusion Database, but are shown as pairs, all the better to compare one form of beauty with another.

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by Richard W. Hughes
Jade Buying Guide •

This article discusses the factors that influence quality and what to look for when buying both jadeite and nephrite. A list of jade auction records is also included.

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