Pezzottaite with Multiple Cat’s-Eyes
The Tokyo laboratory examined a purplish pink pezzottaite cabochon displaying multiple cat’s-eyes.
New Väyrynenite Production from Nigeria
A new source of väyrynenite produces specimens in larger sizes with higher clarities than material from other sources.
Imitation Seed Pearl with Blue X-Ray Fluorescence
X-ray fluorescence screening is used to identify an imitation in a submission of more than 9,000 seed pearls.
Iridescent Gems Cut from Hinge Ligament of South Sea Pearl Oyster (Pinctada maxima)
Biogenic material from a pearl oyster is used to produce a new eye-catching blue-green iridescent gem material.
Three Large Natural Hollow Pinctada radiata Pearls
Three large natural pearls with hollow interiors reportedly from Bahrain are studied in the Mumbai laboratory.
HPHT-Processed Natural and Laboratory-Grown Diamonds with Counterfeit Inscriptions
The Dubai laboratory reports on four diamonds inscribed with fraudulent GIA report numbers.
Exceptional Nacre Thickness of Hybrid Akoya Bead Cultured Pearls
GIA’s Bangkok laboratory reports on a hybrid mollusk species that can produce bead cultured pearls with a thicker nacre layer.
CVD-Grown Diamond with Unusual Cause of Greenish Color
A previously unidentified cause of green color in CVD-grown diamonds is detected for the first time in a diamond submitted to the Carlsbad laboratory.
GIA 7 Pearl Value Factors: An Update on Nacre Classification
A new nacre scale is established in the GIA 7 Pearl Value Factors classification system.
“Goose Bumps” on South Sea Pearl
Pinpoints densely cover the surface of a golden South Sea pearl.
Unique Trapiche Grossular from China
Grossular crystals cut along specific orientations reveal a distinct trapiche structure.
Unusual Patterns in Diamonds Composed of Dark Micro-Inclusions
Two natural diamonds exhibiting dark micro-inclusions are compared in the Carlsbad laboratory.
The Science of Phenomenal Gems, a Summary of Pegmatites, and a Cutter’s Remarkable Journey
An overview of the Summer 2025 Gems & Gemology content.
Ben Kho: From Rough Beginnings to Brilliant Mastery
Profiles the extraordinary life and work of Ben Kho, from a young entrepreneur in Cambodia to an award-winning gem cutter.
Structures Behind the Spectacle: A Review of Optical Effects in Phenomenal Gemstones and Their Underlying Nanotextures
Provides a comprehensive summary of the special optical effects in gemstones, including opalescence, chatoyancy, asterism, schiller, and iridescence, and investigates the submicron inclusions and nanotextures in each type of phenomenal stone.
Gem Granitic Pegmatites
Describes the geology, mineralogy, and formation of granitic-composition pegmatites and provides a summary of their worldwide occurrences.