Agate
from the Antique Jewelry University
Agate, a banded chalcedony variety, 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. Agate's banding, formed as layers of chalcedony, made it a perfect gemstone for glyptography as in cameos and intaglios. Usually the cameos were, and are, carved with the white layer in relief, while in the intaglios the graph is carved into a darker layer to reveil the lighter layer below.
The name agate is derived from the Achatus river in Sicily (now named the Dirillo river) were large amounts of this gem were discovered as early as 300 BC. During the Gallic wars, agate deposits were discoverd along the Nahe river (a tributary to the Rhine) in Germany. The gem-cutting facilities set up there by the Romans survived until 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.
The ancient Egyptians believed that gray agates when worn around the neck would protect against and heal stiffnes of the neck. Moss agate, according to the Romans, had a divine power and an agate stone was used to grind ingredients for lotions and other ointments on, believing 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 relieved thirst and reduced one's temperature. In the Book of Saxon Leechdoms (1864) other tailsmanic uses are attributed to this gemstone as preventing harm from thunder, sorcery, poison, drunkenness and demonic possession.
During Victorian times 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.
Many attributes have been given to agates as ability to aid in love, wealth, good luck, longevity, courage, protection andhealing, 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 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 | Dying |
| Country of origin | Agate is found throughout the world |
| Agate care | |
| Ultrasonic cleaning | Not safe |
| Steam cleaning | Not safe |
| Warm soapy water | Safe |
| Chemical attact | Sensitive to chemical attacks |
| Light sensitivity | None |
| Heat sensitivity | Sensitive to thermal shock |