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 ...

Learn the product knowledge and grading skills to effectively buy inventory and build confidence when buying and selling akoya, South Sea, Tahitian and freshwater pearls. You will be taught GIA’s 7 ...

Miners collect spinels from gravel at the end of a long day at Man Sin. Photo by Vincent Pardieu, © GIA. In the spring of 2001, I was studying gemology in Yangon ...

Gem-quality synthetic diamond crystals weighing up to 11 ct have been grown in limited numbers at the De Beers Diamond Research Laboratory since the 1970s. These crystals have been produced strictly ...

With proper care, citrine is a beautiful and versatile gemstone for jewelry use. – Robert Weldon Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or ...

Below is the list of recognized holidays when GIA locations will be closed.

Consumers now, more than ever, have a heightened awareness of sustainably and ethically sourced products. The GIA Diamond Origin Report uses scientific evaluation to provide confirmation of a ...

Figure 1. The bright red faceted ruby in this gold ring is from the large and potentially productive Snezhnoe deposit in Tajikistan. Photo by Zamoniddin Z. Nasriddinov. Discovered during the late ...

Figure 1. The color zoning of amethyst from Boudi often displays a characteristic hourglass shape. Photo by Abdelghani El Harfi and Salahaddine Mouaddib. For 25 years, the Moroccan locality of Boudi ...

Fancy color diamonds are among the rarest and most valuable gemstones. Diamonds in the normal color range are colorless through light yellow and are described using the industry’s D-to-Z color-grading ...

One of the greatest concerns with emerald filling is the degree of clarity enhancement such treatment represents. Stones that appear to have excellent clarity with the unaided eye are often revealed ...

Despite the commercial value of natural-color diamonds, distinguishing them from treated diamonds remains a significant identification challenge. While some diagnostic visual features exist ...