Brazilian copper-bearing tourmaline was formed by direct crystallization from a hydrous melt, rich in boron and lithium with an unusual concentration of copper, at the early stage of pegmatite ...

Carat weight, or mass, is just one of many gemstone properties measured at GIA (box A). Measurements of physical dimensions and facet angles of polished gemstones, assessment of color and ...

Pursue your passion Whether you’re taking the next step in your professional journey or starting a new career, GIA courses and diploma programs prepare you for success. We offer the finest gem and ...

Examination of samples of faceted "Ocean green" topaz reveals that this material has been irradiated in a nuclear reactor. An earlier reactor-irradiation experiment suggests that temperature ...

Consumers now, more than ever, have a heightened awareness of sustainably and ethically sourced products. The GIA Diamond Origin Report uses scientific evaluation to provide confirmation of a ...

ABSTRACT In southeast Vietnam, gem-quality anorthoclase is found as megacrysts in Cenozoic alkali basalt. The crystals are transparent to translucent with vitreous luster and can be near-colorless, ...

Results from spectroscopic analyses of GE POL high-pressure high-temperature (HPHT) annealed nominally type IIa diamonds are presented, and these spectral characteristics are compared with those of ...

GIAの教育に関するストーリー 宝石・宝飾業界における知識と信頼性が欠けていることを懸念していた宝石商によって設立されたGIAは、一般市民の方々を保護し知識を普及することに注力する非営利組織です。1931年以来、GIAは、ダイヤモンドの品質を示す4CおよびGIA真珠の7つの評価要因™を開発 ...

Gems & Gemology, the professional quarterly of GIA, debuted in 1934. Appearing in the 306 th issue, this article looks back at the first 75 years. By reviewing the journal’s milestones, it also traces ...

以下是 GIA 将休业的法定假期列表。 2025 年 5 月 5 日（星期一） 玛哈•哇集拉隆功国王陛下加冕（补假） 2025 年 5 月 12 日（星期一） 卫塞节（补假） 2025 年 6 月 3 日（星期二） 王后陛下诞辰 2025 年 7 月 10 日（星期四） 守夏节 ...

The June Hong Kong Jewellery & Gem Fair opens on June 22, a mid-year trading event for the gem and jewelry trade. Visit GIA at booth 3M100. Learn about sales tools, aids and apps available through the ...