Pink Diamond with Mottled Appearance
Examination of a Fancy Deep brownish orangy pink diamond reveals evidence of treatment to enhance its color.
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.
Low-Heft Hollow Natural Pearl with an Opening
Organic-rich material is observed through an opening in a hollow natural pearl.
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.
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.
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.
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.
Unusual Yellow Diamond with a Complex Growth History
A combination of growth and dissolution features contribute to a yellow diamond’s unique shape.
Diamond Ring Prize from an Arcade-Style Claw Game
A diamond ring from a claw game in Japan is analyzed.
Gaseous Carbon Dioxide Phases in Paraíba Tourmaline
Immiscible two-phase fluid inclusions are investigated in a 0.48 ct Paraíba tourmaline.
Palaeoclavaria burmitis Inclusions in Burmese Amber
Fungal inclusions are studied in two specimens of Burmese amber.
Blue Color in Quartz Caused by Elbaite Inclusions
Blue needle-like inclusions are analyzed in three quartz spheres.
Converge 2025 Speaker Presentations
A summary of presentations from 24 industry-leading experts at Converge.
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.
New Red Garnet Production from Northern Vietnam
GIA studies a selection of rough and cut garnet from a new source in northern Vietnam.
Reconstructed Specimens and the Rise of Deceptive Practices in Pakistan
A report on the increase of artificially assembled or altered specimens circulating in Pakistan’s local gem markets.
The Diversity of Gemstone Deposits
Investigates deposits known for producing multiple gemstone species and the conditions that create their distinct geological settings.
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.
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