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.
Characterization of Tarnish Spots in Chinese High-Purity Gold Jewelry
Examines the origin and nature of tarnish spots in high-purity gold and how they can be avoided.
The Origin of Montana’s Alluvial Sapphires
Microscopic and chemical analysis may provide clues to the original source of Montana’s alluvial sapphires and help distinguish them from sapphires with overlapping properties.
The Grand Sapphire of Louis XIV and The Ruspoli Sapphire
Archival research and gemological characterization reveal the true story of this 135.74 ct blue sapphire from the French crown jewels.
Splendor in the Outback（奥地の輝き）：オーストラリアのオパール産地への訪問 (英語)
Documents a trip to the renowned opal fields of Lightning Ridge, Koroit, Yowah, and Quilpie.
Book Review: Collector’s Guide to Herkimer Diamonds
Review of Collector’s Guide to Herkimer Diamonds, by Michael R. Walter.
Garnets, Sapphires, Opals, and Tarnish on High-Purity Gold
Grandidierite from Madagascar
An unfamiliar rough fragment acquired from Madagascar may point toward a new source of grandidierite.
Rubies from a New Deposit in Zahamena National Park, Madagascar (英語)
A field expedition from GIA Bangkok explores a new ruby deposit and collects specimens for study.
Two Large CVD-Grown Synthetic Diamonds Tested by GIA (英語)
Two near-colorless rounds, weighing 3.23 and 2.51 ct, were the largest CVD-grown synthetic diamonds GIA has examined.
Large Natural Fossil Blister Pearls from Tridacna (Giant Clam) Species
Two blister pearls attached to a host shell believed to have fossilized during the later Pleistocene period and discovered in southeastern Kenya are studied.
34th International Gemmological Conference
A report from the 34th IGC, held in Vilnius, Lithuania in August 2015.
Demantoid Garnet with Giant Fluid Inclusion
A New Natural-Color Bluish Green Chalcedony
A new type of African chalcedony with the trade name “Aquaprase” shows unique composition and attractive color.
A Natural Pearl with an Intriguing Internal Structure
A semi-baroque pearl with an unusual radial feature is submitted to the Bangkok lab for testing.
Stars Are Out in Paraíba Tourmaline
Rare material from Brazil features four-ray stars under point-source light.
Graphite Inclusions Forming Octahedral Outline in Diamond (英語)
An inclusion outlined by minute graphite crystals within a diamond create an octahedral shape.
Two Large Natural Pearls Reportedly from Spondylus and Trochoidea Species Mollusks
Natural pearls of unusual size and unique appearance are retrieved from the west coast of Mexico and examined in GIA’s New York lab.
Winter 2015 G&G Publication Information
This document provides the publication information for Gems & Gemology
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