by E. Billie Hughes

A Burmese sapphire shows a celestial scene both externally and internally.

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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

An included calcite crystal within an unheated Burmese ruby displays dramatic twinning planes.

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by E. Billie Hughes

Surface-reaching growth tubes in a sapphire provide insight into the gem’s origin and treatment history.

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by E. Billie Hughes
Oiled Ruby

A ruby’s surface-reaching cavity is filled with red oil.

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by Richard W. Hughes
Crystal Optics • Gem and Crystal Optical Properties • Lotus Gemology

The optical properties of crystals are intimately related to their crystal structures. This article examines the precise relationship between optic character and sign and crystal structure.

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by E. Billie Hughes
Beyond Octahedra • Inclusions in Spinel

A look into the world of spinel inclusions that goes beyond simple octahedral crystals.

 

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by E. Billie Hughes
A Sapphire's Secret

At the Lotus Gemology laboratory in Bangkok, we often get parcels of relatively uniform stones. But sometimes it is in this routine testing that we uncover surprises.

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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
From Peacock to Pigeon's Blood: Deconstructing Lotus Color Types

บทคัดย่อเรื่องการจำแนกสีทับทิมและแซฟไฟร์ ที่ใช้ในโลตัสเจมโมโลจี

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