The 75.47-carat Hooker Emerald was worn by Ottoman Sultan Abdul Hamid II, the last sultan of the Ottoman Empire. Photo by Chip Clark, courtesy Smithsonian Institution, National Museum of Natural ...

A look at the history of analytical instruments used for gem testing. UV-Vis-NIR spectroscopy measures how gemstones absorb and interact with light across the ultraviolet, visible, and near-infrared ...

Cultured pearls come in different sizes, shapes, and colors. Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most ...

Figure 1. The sparsely populated high desert of eastern Oregon is home to three localities producing natural copper-bearing labradorite feldspar. In this view of Lake County’s Dust Devil mine, the ...

Figure 1. These 20 completely non-nacreous pen pearls, from the group of 22 samples in this study, are set against a pen shell displaying both nacreous (left) and non-nacreous areas (right). Photo by ...

Search a city or postal code to find retailers who carry GIA-graded diamonds or have GIA-trained staff. Results will include addresses, store hours and directions. Store hours reflected on Retailer ...

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.

The Diamond and Diamond Grading eLearning course brings to life the skills needed to grade the color, clarity and cut of diamonds through video, graphics, images and text.

The September birthstone is sapphire – a gem that’s been cherished for thousands of years. Although the term sapphire usually refers to the blue variety of corundum (ruby is the red variety), this ...

This 3.28-carat Paraíba tourmaline's vivid violetish blue hue rivals the finest sapphires. Because of this tourmaline's rarity, its per-carat price is also likely to rival the price of fine sapphire.

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 ...

The Dom Pedro aquamarine obelisk by gem sculptor Bernd Munsteiner is the largest cut aquamarine. - Eric Welch, courtesy Smithsonian Institution The name “aquamarine” is derived from two Latin words: ...