Gemstone Encyclopedia

Education

Gemstone Encyclopedia

Get to know your gemstones. We organize our most commonly chosen gems with their care, history, and notable qualities.

Gold and emerald necklace, Roman, 1st–2nd century CE.

Emerald

Emerald is a vibrant green beryl and a favorite of Cleopatra's. Expect to see inclusions that dealers like to call an internal “jardin,” or garden. Due to the crystal shape emeralds are commonly cut as rectangular step cuts called emerald cuts.

Be extra gentle with your emerald jewelry. Light, chemicals, heat, and steam can all damage the stone. Clean with soap and water only.

GIA's Emerald Care Guide

Lighter, Pierre Schlumberger, 1939

Ruby

Rubies get their characteristic fire from the presence of chromium. They are sensual and burgeoning with fire.

Corundum (ruby and sapphire) is relatively hard—9 on the Mohs scale. It is an excellent choice for rings and other jewelry subject to daily wear.

GIA's Ruby Care Guide

Necklace with cameo of Veronica's Veil, Firm of Castellani, ca. 1870

Sapphire

Sapphires have captivated mystics, royalty, and jewelers for millennia, symbolizing wisdom and nobility. As a variety of the corundum mineral, they are prized for their brilliant color and exceptional durability. They come in all colors.

Corundum (ruby and sapphire) is relatively hard—9 on the Mohs scale. This makes it a great choice for rings and other mountings subject to daily wear.

GIA's Sapphire Care Guide

Oval gem with Kassandra kneeling at the Palladion, Greek, Late Hellenistic Period. late 1st century B.C.

Aquamarine

Garnet ring stone, Signed by Apollonios, ca. 1st century BCE

Garnet

Garnet refers to a group of gemstones treasured in jewelry since the Bronze Age. Their name derives from the Latin granatus, inspired by their resemblance to pomegranate seeds in both shape and color.

Garnets have been among the most popular gemstones in jewelry throughout history. They can provide a lifetime of enjoyment with proper care.

GIA's Garnet Care Guide

image by Jeff Scovil.

Tourmaline

Its name is derived from the Sinhalese tōramalli.

Brightly colored Ceylonese gem tourmalines were brought to Europe in great quantities by the Dutch East India Company to satisfy a demand for curiosities and gems. Tourmaline comes in a range of colors from dark green to pinkish purple and has one of the widest color ranges of any gem.

GIA's Tourmaline Care Guide
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