Identification of Yellow Cultured Pearls from the Black-Lipped Oyster Pinctada Margaritifera

Although the Pinctada margaritifera oyster usually is associated with the black pearls cultured in French Polynesia, it also can produce attractive large yellow cultured pearls, among other colors.

続きを読む

Star of the South: A Historic 128 Ct Diamond

This article presents the first complete gemological characterization of the historic 128.48 ct Brazilian diamond known as the Star of the South.

続きを読む

Portable Instruments and Tips on Practical Gemology in the Field

続きを読む

Liddicoatite Tourmaline from Anjanabonoina, Madagascar

続きを読む

The Ultimate Gemologist:A Tribute to Richard T. Liddicoat

On this occasion—the celebration of Richard T. Liddicoat’s 50 years guiding Gems & Gemology—it is fitting to review his enormous impact on the field of gemology.

続きを読む

An Update on “Paraíba” Tourmaline from Brazil

Vivid blue, green, and purple-to-violet cuprian elbaites, renowned in the gem trade as “Paraíba” tourmalines, continue to be recovered in small amounts from northeastern Brazil.

続きを読む

“Voices of the Earth”: Transcending the Traditional in Lapidary Arts

Jewelry designer Paula Crevoshay showcases the work of some of North America’s leading lapidaries.

続きを読む

Spessartine Garnet from Ramona, San Diego County, California

For most of the 20th century, the principal source of fine spessartine was the area around the Little Three mine near the town of Ramona in southern California.

続きを読む

Jeremejevite: A Gemological Update

続きを読む

Modeling the Appearance of the Round Brilliant Cut Diamond: An Analysis of Fire, and More about Brilliance

This second major article in a three-dimensional modeling study analyzes fire – the visible extent of light dispersed into spectral colors.

続きを読む

A New Method for Imitating Asterism

Several gems were recently examined that showed stars with an unnatural appearance or an unusual number of rays.

続きを読む

Spectral Reflectance and Fluorescence Characteristics of Natural-Color and Heat-Treated “Golden” South Sea Cultured Pearls

A comparison study was made between the yellow and white nacre of the gold-lipped Pinctada maxima oyster shell and 65 yellow cultured pearls.

続きを読む

The Current Status of Chinese Freshwater Cultured Pearls

Chinese freshwater cultured pearls (FWCPs) are assuming a growing role at major gem and jewelry fairs, and in the market at large.

続きを読む

オーストラリアのアーガイルダイヤモンド鉱脈の発見と採鉱 (英語)

Australia’s Argyle mine has set records for volume since its establishment in 1983, and is additionally noted for its rare pink diamonds.

続きを読む

Ammolite: Iridescent Fossilized Ammonite from Southern Alberta, Canada

続きを読む

Gemstone Enhancements and Detection in the 1990s

Gemstone enhancements and their disclosure became the most important gemological issue for the jewelry trade in the 1990s.

続きを読む

Gem Localities of the 1990s

続きを読む

Sapphires from Antsiranana Province, Northern Madagascar

Since 1996, large quantities of yellow to blue sapphires have been recovered from alluvial deposits derived from basaltic rocks in northern Madagascar.

続きを読む

Gem-Quality Haüyne from the Eifel District, Germany

Haüyne is a rare mineral and an extremely rare gemstone.

続きを読む

Pre-Columbian Gems and Ornamental Materials from Antigua, West Indies

Two archeological sites that were discovered recently on the island of Antigua appear to have had flourishing lapidary industries.

続きを読む

前へ99 / 146 ページ次へ

こちらもご覧ください

YMAL GIA Ed
通学やオンラインでの教育について学ぶ
Learn About NextGem
GIA ネクストジェム(NextGem) ダイヤモンド研修 小売業向け
Explore GIA Laboratory Promotional Offers
GIAラボラトリーの特別オファーを見る
Shop the GIA Store
GIAストアで ショッピング