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The authors present the mineralogical and gemological properties of rubies found recently in the Morogoro area of Tanzania that have many features in common with rubies from Myanmar (Burma) and other comparable marble-type deposits.

Two Near-Colorless General Electric Type-IIA Synthetic Diamond Crystals

Gemological examination of two near-colorless, isotopically pure, carbon-12 synthetic diamonds grown recently by General Electric reveals short-wave ultraviolet luminescence behavior, a cathodoluminescence pattern, and small metallic inclusions that are typical of other gem-quality synthetic diamonds.

Two Treated-Color Synthetic Red Diamonds Seen in the Trade

Two dark brownish red faceted stones, recently submitted to the GIA Gem Trade Laboratory for standard origin-of-color reports, were found to be treated synthetic diamonds.

An Update on Filled Diamonds: Identification and Durability

This report focuses on recent products from Yehuda/Diascience, Koss & Schecter Diamonds (Genesis II), and Clarity Enhanced Diamond House (a subsidiary of Goldman Oved Diamond Co.).

Introduction to Analyzing Internal Growth Structures: Identification of the Negative d Plane in Natural Ruby

This article presents the methods and instruments needed to analyze the internal growth structures of corundum.

Multicolored Bismuth-bearing Tourmaline from Lundazi, Zambia

Tourmalines from an alluvial deposit near Lundazi in Zambia consist of color zoned pink/colorless/yellow-green “watermelon” nodules.

Observations on GE-Processed Diamonds: A Photographic Record

Observations made at GIA on 858 GE-processed diamonds revealed several interesting features that may be diagnostic of this kind of diamond. Specifically, a significant percentage exhibited a slightly hazy appearance, noticeable internal graining, and other unusual internal features.