Agate

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Antique Dendritic Agate and Diamond Brooch. Photo Courtesy of Lang Antiques.

Agate, a variety of chalcedony, occurs in many different colors and in all degrees of diaphaneity - although mainly opaque to translucent. There are many agate varieties named after specific locations where they were found or named after a physical characteristic as with moss agate. Banded agate (also known as onyx), formed as layers of chalcedony, making it a perfect gemstone for glyptography as seen in cameos and intaglios. Usually the cameos were, and are, carved with the white layer in relief, while in the intaglios the design is carved into a darker layer to reveal the lighter layer below.

The name agate is derived from the Achatus river in Sicily (now named the Dirillo river) where large amounts of this gem were discovered as early as 300 BC. During the Gallic wars, agate deposits were discovered along the Nahe river (a tributary to the Rhine) in Germany. The gem-cutting facilities set up there by the Romans survive to present day and, although the deposits are now depleted, Idar-Oberstein - on the Nahe river - is still the major lapidary center of Europe. Today the agates cut there are imported from Brazil and other locations.


Jewelry from Scottish agate came into fashion after Prince Albert bought Balmoral Castle in 1848 and many lovely examples of this type are highly coveted by collectors today.

The ancient Egyptians believed that gray agates when worn around the neck would protect against and heal stiffness of the neck. Moss agate, according to the Romans, had a divine power and ingredients for lotions and other ointments were ground on an agate stone in the belief that it would improve one's eyesight and/or disposition. Other cultures, Persian and Asian, relied on agate as an antidote to fevers by placing the agate in the mouth. It was also thought to relieve thirst and reduced one's temperature. In the Book of Saxon Leechdoms (1864) other talismanic uses are attributed to this gemstone such as preventing harm from thunder, sorcery, poison, drunkenness and demonic possession.

Qualities attributed to agates include an ability to aid in love, wealth, good luck, longevity, courage, protection and healing, balance, harmony, generosity, strength, security and the appreciation of nature. The ability to discover one's natural talents is also attributed to agate.

Due to the association with precision, agates are also considered useful talismans for accountants and bankers.


Gemological information for agate
Color All colors
Crystal Structure Polycrystalline
Refractive Index 1.53-1.54
Durability Excellent
Hardness 6.5
Family Quartz
Similar stones Chrysoprase, Jasper, Carnelian, Bloodstone, Onyx
Treatments Dyeing
Country of origin Agate is found throughout the world
Agate care
Ultrasonic cleaning Not safe
Steam cleaning Not safe
Warm soapy water Safe
Chemical attack Sensitive to chemical attacks
Light sensitivity None
Heat sensitivity Sensitive to thermal shock
Lang Antiques
Lang Antiques