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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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Solution-Generated Pink Color Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines
Solution-Generated Pink Color Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines from Mozambique

Several transparent, faceted, blue to blue-green copper-bearing tourmalines containing growth tubes and cracks surrounded by sleeves of pink color were examined for this report.

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Vanadium and Chromium-Bearing Pink Pyrope Garnet: Characterization and Quantitative Colorimetric Analysis

This type of pink pyrope garnet, believed to have been mined in Tanzania, shows a distinct color-change phenomenon resulting from its unique chemical composition.

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Santa Terezinha De Goias Emeralds
The Santa Terezinha De Goias Emerald Deposit

Brazil has become a leading producer of emeralds; this article examines one of the most significant deposits.

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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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Drilled natural pearls examined in this study.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study

Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.

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Dalmatian stone samples
True Colors of “Dalmatian Jasper”

Discusses the mineralogical composition and provenance of this spotted decorative gemstone.

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Various colors of nephrite
Characterization of Mg and Fe Contents in Nephrite Using Raman Spectroscopy

Evaluates the usefulness of Raman spectroscopy in distinguishing the color varieties of nephrite based on the relative ratio of Mg to Fe concentration.

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Paula Crevoshay’s “Yogo Columbine” sapphire pendant
The Role of Silicon in the Color of Gem Corundum

Considers the previously unreported but critical impact of silicon on the coloration of gem-quality sapphire.

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