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.

続きを読む

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.

続きを読む

Summer 2026 G&G Available Now

An overview of the Summer 2026 Gems & Gemology content.

続きを読む

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.

続きを読む

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.

続きを読む

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.

続きを読む

Six-Rayed Star Quartz Containing Exsolved Rutile Needles

Needle-like hematite and rutile inclusions are identified in two six-rayed star quartz specimens.

続きを読む

An Unusual Yellow Raindrop Turquoise

A unique specimen of turquoise with yellow raindrop-like patterns is examined.

続きを読む

In Memoriam: Harold Van Pelt, 1925–2026

The gemological community mourns the loss of gem photography pioneer Harold Van Pelt.

続きを読む

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.

続きを読む

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.

続きを読む

Carved Natural Diamond Panther Face

The Mumbai laboratory reports on a unique carved natural diamond set with two Zambian emeralds.

続きを読む

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.

続きを読む

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.

続きを読む

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.

続きを読む

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.

続きを読む

Twinned Calcite with Realgar Inclusions

Vivid red to orange-red realgar inclusions are observed in a contact-twinned calcite host.

続きを読む

“Fungal Hyphae” in a Mabe Pearl

A mabe pearl exhibits an unusual pattern of intersecting subsurface channels, likely formed by shell-boring parasites.

続きを読む

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.

続きを読む

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.

続きを読む

前へ1 / 238 ページ次へ

あなたにおすすめ

YMAL GIA Ed
GIAのロンドン新キャンパスを発見
Learn About NextGem
GIA NextGem™ 小売業向けダイヤモンドトレーニング
Explore GIA Laboratory Promotional Offers
GIAラボのプロモーションオファーを探る
Shop the GIA Store
GIAストアで購入