Diamond Ring Prize from an Arcade-Style Claw Game
A diamond ring from a claw game in Japan is analyzed.
Unusual Yellow Diamond with a Complex Growth History
A combination of growth and dissolution features contribute to a yellow diamond’s unique shape.
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.
Filled Natural Hollow Heart-Shaped Pearls
Examination of four heart-shaped pearls reveals cavity filling and plugging to improve durability.
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.
Large Peridot from Myanmar with an Eight-Rayed Star
An eight-rayed star peridot with a star system made up of two different sets of inclusions is described for the first time.
Trapiche Pattern Formation of Grossular Garnets
GIA’s Tokyo laboratory examines three grossular garnets displaying six-rayed black inclusions arranged in a snowflake-like pattern.
Type IIa/IaB Diamond Showing Transient Type IIb Responses
A 2.50 ct natural type IIa/IaB diamond submitted to the Dubai laboratory shifts to type IIb after deep-UV excitation.
Low-Heft Hollow Natural Pearl with an Opening
Organic-rich material is observed through an opening in a hollow natural pearl.
Extraordinary Large Bicolor Natural Rough Diamond
A 37.41 ct natural rough diamond with distinct pink and colorless zones is examined at GIA’s Botswana laboratory.
Pink Diamond with Mottled Appearance
Examination of a Fancy Deep brownish orangy pink diamond reveals evidence of treatment to enhance its color.
Prismatic Bicolor Dumortierite Crystal
A 63.17 ct dumortierite rough crystal is examined in the Bangkok laboratory.
Quench-Crackled and Dyed Laboratory-Grown Sapphire
The Carlsbad lab receives a laboratory-grown colorless sapphire with weblike fractures containing concentrations of dye.
Starburst Cloud Inclusions in Diamond
Clusters of micro-inclusions form starburst-patterned clouds in a 2.50 ct Faint yellow-green round brilliant diamond.
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.
External Morphology and Internal Zonal Structure of Macle Diamond
Investigates the morphological changes of macle diamonds during the growth process by exploring their three-dimensional internal zonal structure.
The Diversity of Gemstone Deposits
Investigates deposits known for producing multiple gemstone species and the conditions that create their distinct geological settings.
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.
Raw Brilliance: Nature’s Diamond Sculptures
Showcases the diverse natural shapes of rough diamonds and explores how geological processes create their unique forms.
Al Gilbertson Receives Robert M. Shipley Award
GIA’s Al Gilbertson receives the American Gem Society’s highest honor.
