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 ...

Some natural opals, mostly from Ethiopia, show a macroscopic finger-like structure called a digit pattern. This pattern consists of vertical columns that are more or less parallel, separated by a ...

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, ...

The green turquoise cabochon, from an American mine, might become part of a designer’s unique jewelry piece. The even blue color of the cabochon on the right would be called “Persian blue” in the ...

However gem quality diamonds are fashioned from the original crystal shape they possess a combination of brightness, sparkle, fire, and sense of purity not matched by other gems. - Jeff Scovil, ...

The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds colored gray to blue to violet. Twenty such diamonds were studied to investigate the relationships ...

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.

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 ...

Colorless synthetic quartz that shows obvious Brazil-law twinning has been grown over a seed plate of natural amethyst that is twinned according to the Brazil law. Although commercially available ...

Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA.

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 ...