Emerald

Gem faceters and jewelry enthusiasts alike should learn about gemstone toxicity. This table has toxicity ratings for 280+ gems, based on their…

Although many gems show a cat’s eye effect, when the term “cat’s eye” is used alone, it always refers to the rare gemstone chrysoberyl.…

What qualities should you look for when padparadscha sapphire buying? Learn about the sunset colors and other properties of these gems.

Discover the rare and mesmerizing alexandrite gemstone. Learn all about the incredible color-changing properties, value factors, and origins…

A gemstone’s birefringence is a measure of its double refraction. Learn how to use it to identify gems and see the effects birefringent gems can…

Brookite usually occurs in very dark colors, transparent only in small fragments. Cuttable crystals are exceedingly rare, making attractive…

We’ve tallied your opinions from our gem treatment survey. Are treated gems natural? How much should they cost? With a wide variety of attitudes…

Triphylite is one of the world’s rarest gems. The IGS had the extraordinary privilege of examining a discovery of facetable material from Brazil…

What will 2018 bring to the world of gems and jewelry? Learn about the latest gem trends — everything from colors, designs, and settings to the…