This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

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.

Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading Presents findings from observations of oval-, pear-, and marquise-shaped diamonds, laying the groundwork ...

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 ...

Large quantities of rubies—both rough and faceted—from a commercially important new source in Myanmar (Burma) have been available on the Bangkok market since 1992. The ruby crystals from the Mong Hsu ...

This ancient necklace dates to 2000BCE. An inscription on the center stone is a South Arabian script from the 8th century BCE. - From "Gems and Gemstones: Timeless Natural Beauty of the Mineral World" ...

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 ...

Although various forms of paints and coatings intended to alter the color of diamond have likely been in use for almost as long as diamonds have been valued as gems, the modern era of diamond ...

Students examine the technical expertise needed to grade, buy, and sell diamonds with the insight of a seasoned professional. Coursework explores the GIA diamond grading procedures to assess the 4Cs – ...

Harness the power of knowledge with the industry-leading instruments that GIA uses in its grading laboratories. Representing more than 85 years of research and the combined expertise of GIA’s ...

Students explore more than 60 species of common and collector gemstones found in the marketplace. Subjects covered include the GIA Colored Stone Grading System, gemstone formation, composition, ...

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, ...