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.
The Very Deep Origin of the World’s Biggest Diamonds
Explores an exceptional family of diamonds, referred to as “CLIPPIR” (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular, and Resorbed), that formed in a superdeep environment.
True Colors of “Dalmatian Jasper”
Discusses the mineralogical composition and provenance of this spotted decorative gemstone.
Synthetic Star Sapphires and Rubies Produced by Wiede’s Carbidwerk, Freyung, Germany
Details the process used by Wiede’s Carbidwerk to produce star synthetic corundum from the mid-1950s through the 1970s.
Photoluminescence Spectra of Emeralds from Colombia, Afghanistan, and Zambia
Compares PL spectroscopy data of 48 emerald samples from three countries to evaluate the usefulness of the technique in geographic origin determination.
Big Sky Country Sapphire: Visiting Montana’s Alluvial Deposits
Documents a visit to the upper Missouri River and Rock Creek sapphire mining areas.
Variscite from Central Tajikistan: Preliminary Results
A look at the gemological properties and chemical composition of this light blue to light green to green gem material, which is suitable for cabochon cutting.
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.
An Update on Tourmaline from Luc Yen, Vietnam
Reviews the characteristics of tourmaline from pegmatites in the Luc Yen district of northern Vietnam.
Sapphire Chart Article: Suggested Reading on Sapphires and Their Inclusions
Suggested Reading on Sapphires and their Inclusions