Gemological Characterization of Peridot from Pyaung-Gaung in Mogok, Myanmar
Examines the mining and the internal, spectroscopic, and chemical features of peridot from this deposit, which possesses a rich olive green color and is available in large sizes.
History of Emerald Mining in the Habachtal Deposit of Austria, Part I
Contributes to the mining history of Austria’s Habachtal region, which is believed to be one of the earliest emerald deposits.
Blue Sapphires from Mogok, Myanmar: A Gemological Review
A gemological analysis of blue Burmese sapphires from Mogok, based on a series of field expeditions over the last decade.
Faceted Demantoid Garnet with Spectacular “Horsetail” Inclusions
Remarkable “horsetail” inclusions discovered in a demantoid garnet, while their origin and composition remain under discussion.
Color-Zoned Cat’s-Eye Chrysoberyl
The Tokyo lab recently identified a unique localized distribution of cloud-like inclusions in a chrysoberyl.
Spiral Nacre in Natural Pearl
Nacreous pearls are known to have platelet growth resembling fingerprints or topographic maps, but a less common appearance is nacre with a concentric spiral pattern.
Monazite (?) in Quartz
Analysis of a transparent yellow angular crystal inclusion in a Brazilian rock crystal quartz host suggests monazite.
Blue Zircon Reportedly from Malawi
A reported new source of blue zircon in Malawi yields rough material for beautiful finished stones in the gem trade.
Rainbow Graining in Diamond
One of the more subtle inclusion scenes gemologists sometimes observe in natural diamonds is the presence of crystallographically oriented structural defects known as “internal graining.”
Star Rhodochrosite
The Carlsbad lab received a rhodochrosite cabochon featuring rhomboid-shaped fluid inclusions, causing a four-rayed star.
Two Antique Mughal Spectacles with Gemstone Lenses
Unique diamond- and emerald-lensed spectacles from the Mughal Empire were tested in GIA’s New York laboratory.
Colored Stones from the Deep
The first installment of this column discusses the formation of colored stones from the crust-mantle transition and below.
Banded Turquoise from Zhushan County, Hubei Province, China
Researchers examine six specimens of banded turquoise, obtained through long-term cooperation of local miners in Zhushan County.
Burmese Blue Sapphire and Peridot from Mogok and a History of Emerald Mining in Habachtal, Austria
An overview of the Winter 2021 Gems & Gemology content.
Chondrodite in Red Spinel from Mogok, Myanmar
The Bangkok lab recently encountered a single round crystal of chondrodite in red spinel, a possible indicator of Burmese origin.
Radioactive Green Diamond
The Carlsbad lab recently encountered a 2.42 ct green diamond showing signs of radiation treatment by the use of radioactive salts.
Winter 2021 G&G Publication Information
This document provides the publication information for Gems & Gemology
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