クラリティに関するプロット図付きの完全な4Cの評価。セットされていないDからZのカラー範囲の天然カラー ダイヤモンドで、重量は0.15カラット以上のもののみにご利用いただけます。

Jade is one of the most misunderstood gemstones. It is actually two separate materials: jadeite and nephrite. Together, these materials have more simulants than most other gems. Thus, it is important ...

Figure 1. This alexandrite cabochon appears brownish green in fluorescent light (left) and brownish purple in incandescent light (right). The cabochon shows chatoyancy under both forms of illumination ...

Metrology, the science of measurement and its application, plays a critical role in the accuracy of GIA’s research and laboratory services. The metrology team closely monitors the performance of ...

This 376.85-carat tourmaline was carved by O. Hansen, using the colors of the tourmaline as part of the design. - Chip Clark, courtesy Smithsonian Institution, National Museum of Natural History ...

Birthstones are a fun, popular and colorful introduction to the world of gemstones. They appeal to audiences around the world regardless of gender, age, nationality or religion. Birthstones carry ...

Greater amounts of colorless sapphire—promoted primarily as diamond substitutes, but also as natural gemstones—have been seen in the gem market during the past decade. In the absence of inclusions or ...

Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading Presents findings from observations of oval-, pear-, and marquise-shaped diamonds, laying the groundwork ...

活动将于 9 月 7 日至 10 日在加利福尼亚州卡尔斯巴德举行，请注意预定座位 加利福尼亚州卡尔斯巴德 – 2025 年 1 月 27 日 – 融合了美国宝石学会 (AGS) 和美国宝石研究院 (GIA) 独特专业知识的宝石和珠宝行业盛会 Converge 现已开放注册。AGS 成员等业内专业人士可以 ...

9月7日～10日にカリフォルニア州カールズバッドで開催されるイベントへ確実に参加できるようにしましょう カリフォルニア州カールスバッド – 2025年1月27日 – 米国宝石協会（AGS）と米国宝石学会（GIA）の独自の専門知識を結集した特別な宝石・宝飾品 ...

GIA’s laboratories use advanced instrumentation and research to deliver accurate grading, identification, and origin ...