As an international jewelry hub and world destination commercial center, Hong Kong is the quintessential location for the gem and jewelry sector. Combine that with educational powerhouse GIA, and you ...

7.9-cm tall crystal. Both are from Sappat, Kohistan, Pakistan. - Jeffrey Scovil Gem miners find peridot as irregular nodules (rounded rocks with peridot crystals inside) in some lava flows in the ...

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 ...

Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive.

Lattice diffusion is a treatment process that uses heat and chemicals to diffuse an element into a gemstone to artificially change its color. Lattice diffusion–treated sapphires can be any color. In ...

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.

The Robert Mouawad Campus at GIA World Headquarters in Carlsbad offers world-class gem studies with advanced classrooms, a renowned lab, and an iconic museum.

Designed for clients who seek in-depth insights into every aspect of a jewelry item. Comprehensive analysis of the diamonds in an item, including number of stones, shape, estimated carat weight, color ...

Figure 1. This bluish green chalcedony, colored by chromium and nickel, is marketed under the trade name “Aquaprase.” Photo by Kevin Schumacher. A new type of chalcedony (figure 1) was recently ...

Figure 1. Pleochroism in a 15 ct tanzanite, as seen with the unaided eye through the crown and the pavilion sides and ends. Photo by Wimon Manorotkul. In describing colored gemstones, the major ...

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.

Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive.