At the earth’s surface, graphite is the stable crystalline form of carbon, with a density of 2.26 g/cm 3. Diamond is a much more compact form of carbon, with a density of 3.52 g/cm 3, 56% higher than ...

Figure 1. Spinel is available in a wide range of colors, as seen in this suite of round gems weighing 1.47–6.70 ct faceted by Bill Vance. Photo by Robert Weldon/GIA; courtesy of Vance Gems. Spinel has ...

This chart focuses primarily on the types of natural inclusions found in tourmaline, as well as the minerals in which tourmaline can be found as an inclusion. Treatments such as enhancement of ...

Figure 1. The five zircon samples used in this study, ranging in size from 0.56–21.92 ct, were analyzed for radioactive degradation of their crystal structure. Radioactive elements such as thorium and ...

GIA reports represent the highest standard of reliability, consistency and integrity. And now, GIA Report Check is available for all GIA reports, providing you with an additional level of assurance.

Jadeite jade, often cut as a cabochon, is one of the most valuable and culturally significant gemstones. - Courtesy Mason-Kay Fine Jade Jewelry Among gemologists, jadeite and nephrite have long been ...

Zircon’s typical greenish blue color has been referred to as zircon blue. - Lydia Dyer, gem courtesy of John Dyer & Co. Zircon is a gemstone that’s not commonly known among jewelry buyers, which is a ...

This 17.53-carat amethyst displays a rich reddish purple color. - Lydia Dyer, Super Trillion Cut Amethyst gem courtesy of John Dyer & Co. Amethyst has been the most-prized quartz variety for centuries ...

With 65,000 volumes, 230,000 images, 2200 videos, and 1200 periodicals, the Richard T. Liddicoat Gemological Library & Information Center and Cartier Rare Book Repository & Archive is the largest, ...

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 ...

The Robert Mouawad Campus at GIA World Headquarters is the premier gem studies school — fully integrating state-of-the-art classrooms, the famous GIA laboratory, and an internationally recognized ...

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 ...