An Evaluation of Turquoise from the Mona Lisa Mine in Arkansas
Examines samples of Mona Lisa turquoise to identify their chemistry and structure, revealing copper as a major elemental component of the material.
The Primary Sapphire Occurrence at French Bar Sill Along the Missouri River, Near Helena, Montana
Reports on a new source of primary gem-quality sapphire from Montana, comparing its inclusions and trace element chemistry with those from secondary sources in the state.
Temples and Treasures of Southern Asia: A GIA Museum Exhibit
A photo tour of the GIA Museum’s latest exhibit featuring extraordinary crystals and gems central to the cultures of southern Asia.
The Diversity of Gemstone Deposits
Investigates deposits known for producing multiple gemstone species and the conditions that create their distinct geological settings.
Freshwater Akoyas - A Trending Misnomer for Certain Freshwater Pearls
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Quarterly Crystal: Almandine-Pyrope Garnet in Diamond
A diamond octahedron from South Africa hosts a rare yellow-orange almandine-pyrope garnet crystal.
Low-Temperature Heat Treatment of Corundum and the Behavior of the 3161 cm–1 Infrared Band
A study analyzing the thermal behavior of the 3161 cm–1 IR feature in 10 natural corundum samples from various deposits.
Low-Heft Hollow Natural Pearl with an Opening
Organic-rich material is observed through an opening in a hollow natural pearl.
Suspended Pargasite Crystal in Pink Spinel
A euhedral prismatic pargasite crystal is identified in pink spinel.
Two Assembled Pearls
Natural pearl cores are used to simulate the appearance of natural pearl growth in two assembled pearls mounted in a pair of earrings.
Diamond Ring Prize from an Arcade-Style Claw Game
A diamond ring from a claw game in Japan is analyzed.
Sea Urchin–Like 3D Radial Fissures in a Heated Mong Hsu Ruby
Examination of a 1.34 ct ruby reveals a unique inclusion formed during heat treatment.
Quench-Crackled and Dyed Laboratory-Grown Sapphire
The Carlsbad lab receives a laboratory-grown colorless sapphire with weblike fractures containing concentrations of dye.
Unusual Yellow Diamond with a Complex Growth History
A combination of growth and dissolution features contribute to a yellow diamond’s unique shape.
Gersdorffite in Quartz
Gersdorffite inclusions in quartz exhibit either triangular or hexagonal shapes when viewed from different directions.
Prismatic Bicolor Dumortierite Crystal
A 63.17 ct dumortierite rough crystal is examined in the Bangkok laboratory.
Blue Color in Quartz Caused by Elbaite Inclusions
Blue needle-like inclusions are analyzed in three quartz spheres.
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