这一组原石和成品蓝宝石显示了蓝色至紫罗兰色或紫色色彩的广泛范围，以及可以在约戈蓝宝石中发现的由淡到深的色度组合。最大的刻面宝石是一颗 1.44 克拉的垫型切工宝石。由 Bill Vance（比尔·万斯）友情提供。摄影：Kevin Schumacher（凯文·舒马赫） 尽管美国 ...

This 5.30-carat emerald from Brazil has a slightly bluish green color. Courtesy John Parrish, courtesy African, Brazilian, Colombian Gems Incorporated. Emerald has many special qualities, but colored ...

GIA evaluates ruby but does not grade it. A GIA Colored Stone Identification & Origin Report assesses the characteristics of a ruby (weight, measurements, shape, cutting style and color), indicates ...

Those born in January are lucky to have the beautiful and diverse garnet as their birthstone. Garnets are commonly red but also come in an extraordinary range of beautiful colors, including orange, ...

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.

97.45 克拉的火焰帝王拓帕石收藏在菲尔德自然历史博物馆。 - 感谢《宝石与宝石学：矿物世界的永恒自然之美》，作者：Grande & Augustyn，出版社：芝加哥大学出版社。 大多数专家同意拓帕石 (topaz) 这个名字来自古老的希腊名 "Topazios"，原本是红海的一座小岛的 ...

This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...

Emerald, the birthstone for May, has been beloved for millennia, evoking rebirth and renewal. Widely regarded as the definition of green, emerald is the perfect color for spring. From the poetic ...

Diamonds have a long history as beautiful objects of desire. In the first century AD, the Roman naturalist Pliny stated: “Diamond is the most valuable, not only of precious stones, but of all things ...

Learn more about programs and courses offered at GIA's campus in New York City including admission requirements, class schedules, academic policies and more. Stay in touch - complete the form below to ...

Diamond is available in a range of sizes and qualities to fit every consumer's tastes. One of the first things most people learn about diamonds is that not all diamonds are created equal. In fact, ...

Zoltan David is an award-winning artist, and his fourteen one-of-a-kind jewelry pieces in the GIA collection are breathtaking expressions of his inspirations and design philosophies. Some of his work ...