The modern elephant, threatened by extinction, is protected by international agreements banning the sale of ivory from tusks. This trade ban does not apply to ornaments made of mammoth fossil ivory, ...

一月生日石柘榴石是品种最丰富的宝石之一，因为它有许多不同的颜色。柘榴石生日石可在世界各地进行开采，象征着许多不同的乐观情绪。了解更多关于这种独特生日石的信息。 紫水晶是二月 ...

Four similar-appearing yellowish green samples from Block D at Merelani, Tanzania, were identified as diopside and tremolite. The gems are identical in color, but their standard gemological properties ...

Studies carried out at the DTC Research Centre have shown that single-crystal CVD synthetic diamond is clearly distinguishable from natural diamond. This article presents information about the CVD ...

Figure 1. These emeralds from Musakashi, Zambia, range from 0.57 to 4.85 ct. The rough samples were polished with one window on each. The faceted sample measures 6.29 × 5.35 × 3.53 mm and weighs 0.97 ...

2.33カラットのウィンストン レッドダイヤモンド。写真撮影：Robert Weldon、提供：Ronald Winston。 ウィンストン レッドは現在、スミソニアン博物館で公開展示されている カリフォルニア州 ...

GIA is proud to provide the most comprehensive research in the industry with a world-renowned field gemology team and a dedication to acquiring colored stones directly from the source. Our ...

This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

The GIA Laboratory-Grown Diamond Report includes full quality assessment with a plotted clarity diagram. Color and clarity specification are described on the same scale as the GIA Diamond Grading ...

As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated.

The Diamond and Diamond Grading eLearning course brings to life the skills needed to grade the color, clarity and cut of diamonds through video, graphics, images and text.

The beautiful shimmer of light that's characteristic of moonstone is apparent even in its rough form. This special property is maximized by a quality cut. - David Humphrey Moonstone’s delicate beauty ...