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Grayish blue aquamarine
Aquamarine with Unusually Strong Dichroism

This aquamarine's most striking feature was its unusually strong dichroism, displaying very deep blue and pale bluish green colors.

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Multi-colored gems are superimposed on an image of glacier peaks.
Article
Gems and Minerals from the Subarctic

Circumnavigate the boreal reaches of the globe to explore gems from polar regions.

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A heart-shaped piece of pink drusy hangs from a gold chain.
Article
Dreamy Drusy: Minute Crystals Shimmer in Dramatic Designs

Drusy jewelry has surged in popularity in recent years. Celebrities wear it on the red carpet and designers clamor for it at gem shows.

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Interference figures in faceted alexandrite
Pleochroism and Color Change in Faceted Alexandrite: Influence of Cut and Sample Orientation

Shows how alexandrite’s color and color change are affected by cut and the orientation of table facets.

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Assortment of Linde synthetic star rubies and sapphires
Dual-Color Double Stars in Ruby, Sapphire, and Quartz: Cause and Historical Account

Examines a form of asterism comprising two six-rayed stars, one white and one that exhibits the stone’s bodycolor. Firsthand accounts and a survey of patent documents reveal that diffusion has been used to create or enhance this optical phenomenon in synthetic and possibly natural corundum since the 1950s.

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HOC synthetic alexandrite inclusion.
Challenges in Orienting Alexandrite: The Usambara and Other Optical Effects in Synthetic HOC-Grown Russian Alexandrite

Overview and commentary on the 2013 Journal of Gemmology article “Synthetic alexandrites grown by the HOC method in Russia: Internal features related to the growth technique and colorimetric investigation.”

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Titanium-Bearing Synthetic Alexandrite and Chrysoberyl

Overview and commentary on the 2013 Journal of Gemmology article “Titanium-Bearing Synthetic Alexandrite and Chrysoberyl.”

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Natural-Color Pink, Purple, Red, and Brown Diamonds: Band of Many Colors

Summarizes data collected by GIA on more than 90,000 natural diamonds in this color range and presents their gemological and spectroscopic properties.

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Color-change diaspore
The Color Origin of Gem Diaspore: Correlation to Corundum

Examines the color origin of color-change diaspore, known commercially as Zultanite, and compare the effectiveness of the chromophores it shares in common with corundum.

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Canary yellow diamond
Diamond Identification

Abstracts of speaker presentations from the “Diamond Identification” session of GIA’s 2018 International Gemological Symposium.

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