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Há 5 dias · Russian demantoid comes in a wide range of colors, covering all shades of green. Much of the material has a brown color that can become dominant. The finest color is considered a pure, vibrant green with no secondary hues. It is estimated that around 80% of the Poldnevaya mine production has a secondary yellow color, while 15% is apple green ...
Há 5 dias · The finished carving measures 79.5 × 69.8 mm and weighs 322.72 ct. To complement the piece, the center features two sapphires from the Rock Creek area of Montana: a 5.56 ct grayish blue “torus ring” carving and a 0.65 ct padparadscha. Figure 3. Left: David Nassi of 100% Natural, Ltd. showing a collection of unheated spinels he has recut ...
Há 4 dias · GIA 签发第一份钻石分级证书；成为国际珠宝业的标杆。. Crowningshield（克劳宁谢尔德）在使用分光仪检测宝石处理领域完成了突破性的工作。. GIA 出版 Diamond Dictionary（《钻石字典》），迅速成为国际行业参考图书。. GIA 课程得到美国函授委员会（现称为远程教育 ...
Há 5 dias · A GIA team from Education and Lab Services visited the upper Missouri River sapphire deposits in Montana. The first sapphire discovery in the Treasure State, these deposits have been mined for over 150 years. The team witnessed the mining at the richest source, Eldorado Bar, and purchased a mine run to enrich GIA’s corundum collection.
Há 5 dias · Kunzite Description. Kunzite’s beauty is apparent in both its natural crystal and faceted forms. - Robert Weldon. Kunzite is the light pink to violetish purple variety of the mineral spodumene. It’s found in Afghanistan, Brazil, Madagascar, and the US state of California. The gem was named after pioneering gemologist George Frederick Kunz ...
Há 3 dias · Garnets are a set of closely related minerals that form a group, resulting in gemstones in almost every color. Red garnets have a long history, but modern gem buyers can pick from a rich palette of garnet colors: greens, oranges, pinkish oranges, deeply saturated purplish reds, and even some blues. Red garnet is one of the most common and ...
Há 4 dias · Emeralds are formed when chromium, vanadium, and iron are present in the mineral beryl. The varying presence of these three elements gives emerald its range of color. Chromium and vanadium make an intense green color. Iron gives the stone a bluish tint. The most valuable emeralds are bluish-green to green and have a medium to medium-dark tone.
