From the Field: Vietnam
Travel with GIA’s field gemology team to northern Vietnam as they explore local mining and trading communities, revealing the connection between gemstones and their origins.
GIA Knowledge Sessions | Ethiopia's New Paraíba Tourmaline Source: What the Science Reveals
Join GIA expert Dr. Aaron Palke as we unveil groundbreaking research confirming Ethiopia as a significant new source of copper-bearing paraíba tourmaline. Learn how these findings impact origin determination, identification methods, and the broader colored gemstone market as this new production enters the market.
Glass-Ceramics as Imitation Gemstones: A Study on a Silicon-Aluminum-Magnesium-Zinc System
Characterizes silicon-aluminum-magnesium-zinc glass-ceramics and proposes identification criteria to distinguish these imitations from natural and laboratory-grown gemstones.
Determination of Aquamarine in a Brazilian Pegmatite Plate
A bluish green translucent mineral is identified as aquamarine in a large pegmatite plate from Minas Gerais, Brazil.
Rare Colors of Chinese Freshwater Cultured Pearls
Gemologists test a group of freshwater cultured pearls with rare colors ranging from deep purple to orange-red.
Six-Rayed Star Quartz Containing Exsolved Rutile Needles
Needle-like hematite and rutile inclusions are identified in two six-rayed star quartz specimens.
An Unusual Yellow Raindrop Turquoise
A unique specimen of turquoise with yellow raindrop-like patterns is examined.
In Memoriam: Harold Van Pelt, 1925–2026
The gemological community mourns the loss of gem photography pioneer Harold Van Pelt.
Characterization of Red and Orange Spinel from Myanmar and Vietnam
Examines the gemological properties of red and orange spinel from Mogok, Myanmar, and Lang Chap and An Phu in Vietnam, using trace element chemistry to evaluate geographic origin.
Atypical Color Center in Natural Pinkish Brown Diamond
Atypical absorption spectral features are observed in a natural pear brilliant diamond previously submitted as rough to GIA.
Carved Natural Diamond Panther Face
The Mumbai laboratory reports on a unique carved natural diamond set with two Zambian emeralds.
Large South Sea Bead Cultured Pearl with Mille-Feuille Structure
Examination of an extraordinarily large bead cultured pearl reveals an unusual internal structure characterized by widely spaced concentric nacre layers separated by translucent organic material.
Microscopic Marine Organisms in South Sea Cultured Pearls
The Bangkok laboratory documents the first reported discovery of microscopic marine organisms observed in South Sea cultured pearls at GIA.
Reversible Photochromism in a Heat-Treated Sri Lankan Sapphire
A heat-treated Sri Lankan sapphire exhibits a rare reversible color change from very light blue to light yellow after short-wave UV exposure.
Heat-Treated Red Spinel
A purplish red oval mixed cut submitted as a ruby was recently identified as heat-treated spinel at the Hong Kong laboratory.
Twinned Calcite with Realgar Inclusions
Vivid red to orange-red realgar inclusions are observed in a contact-twinned calcite host.
“Fungal Hyphae” in a Mabe Pearl
A mabe pearl exhibits an unusual pattern of intersecting subsurface channels, likely formed by shell-boring parasites.
Leaf-Like Imprint on Non-Nacreous Pearl
Microscopic examination of a non-nacreous natural pearl reveals a distinctive pattern resembling leaves with intricate vein structures.
Reticulated Pattern on Pearl’s Surfaces
Several natural pearls in a multistrand necklace display an unusual reticulated surface texture with deep indentations and prominent ridges.
