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Gemstones - A-Z Gemstones


AGATE Mentioned in the Bible
Origins Brazil, India, Mexico & South Africa
Colours Found Various
Family Chalcedony Quartz
Hardness 6.50 - 7.00
Refractive Index 1.53 - 1.54
Relative Density 2.58 - 2.64

Agate is the banded form of Chalcedony (also spelt Calcedony and correctly pronounced as “Kal-ced-on-ee”, it is the catchall term for cryptocrystalline Quartz) and its name was derived from the site of its discovery, the river Achates (now Dirillo) in southwest Sicily. You will often find beautifully flowing patterns within Agate, which are caused by the presence of iron and manganese.

Legends and lore

Said by the ancients to render the wearer invisible, Agate has been admired by humanity for thousands of years. Its beauty and durability have prompted humankind to use it for both practical and ornamental purposes. Valued by the ancient Sumerians and Egyptians who used it for amulets and ornamental pieces, Agate is one of the oldest known gems. In Roman times, Agate intaglio (a gem carved in negative relief) signet rings were particularly popular.

Agate is mentioned in the Bible as being one of the “stones of fire” (Ezekiel 28:13-16) that were given to Moses and set in the breastplate of Aaron (Exodus 28:15-30). A variety of Agate, Sardonyx is one of the twelve gemstones set in the foundations of the city walls of Jerusalem (Revelations 21:19). As compiled by Andreas, Bishop of Caesurae, one of the earliest writers to tie the Apostles with the symbolism of the twelve gems of Jerusalem, Sardonyx represents the Apostle James. Agate was especially valued during medieval times when one of the more outlandish uses was to bind an Agate to each horn of an ox to ensure a good harvest. The danger here is that your Agated beasts of burden may then become invisible and a little hard to find! Agate is believed to cure insomnia, ensure pleasant dreams, protect against danger and promote strength and healing.

Just the facts

The main conditions necessary for Agate formation are the presence of silica from devitrified volcanic ash, water from rainfall or ground sources, manganese, iron and other mineral oxides that form the white, red, blue, grey, brown or black bands. Agate comes in many different forms ranging from transparent to opaque. Varieties include Blue Agate, Blue Lace Agate, Crazy Lace Agate, Green Agate, Indian Agate, Moss Agate, Fire Agate, Tree Agate, Onyx, Sardonyx and Wood Agate.