Agate is a subvariety of chalcedony, it is a kind of crypto-crystalline
quartz in which the color is distributed in curved layers or bands.
Agate forms by filling a cavity in the host rock (normally volcanic
rock) and most of them are found in the shape of a round nodule and they
have concentric bands which look like the rings of a tree trunk.
Sometimes the bands look like eyes, or scallops and sometimes even like a
landscape with dendritic trees.
Agate is a subvariety of chalcedony, it is a kind of crypto-crystalline quartz in which the color is distributed in curved layers or bands. Agate forms by filling a cavity in the host rock (normally volcanic rock) and most of them are found in the shape of a round nodule and they have concentric bands which look like the rings of a tree trunk. Sometimes the bands look like eyes, or scallops and sometimes even like a landscape with dendritic trees.
Some common colors of agates are yellow, green, black, purple, red, brown, orange, white, bluish-white and reddish-brown. Green and blue agates are the rarest. Although these stones can be found in various rock, agates are classically associated with volcanic rocks but also can be common in certain metamorphic rocks. Sometimes tiny crystals (called drusy) are found within the stone.
The names chalcedony and agate can be interchangeable, although generally the name for the banded varieties of chalcedony is agate. Descriptive names such as picture agate, moss agate, blue lace agate and crazy lace agate are among some of the varieties. Most of the banded types are naturally colored, such as botswana, blue lace, and crazy lace.
Agate is an innovatively created gemstone by nature and one of the first materials known to man. The stone has been used for good luck since ancient times. It was said to quench thirst and protect from fevers. It is a beautiful semi precious gemstone with huge diversity in it. Many other semi-precious stones are in fact forms of chalcedony including onyx, agate, bloodstone and carnelian. Good looks, easy availability and affordable prices are some of few features which make them well liked in the circle of gemstone lovers.
The Sumerian seem to have been the first to use the stone for seals, beads, signet rings and other articles of jewelry. Agates and other chalcedonies were first obtained in Sicily over 3000 years ago from the Achates River and the gem was given its name by Theophrastus, a Greek naturalist and philosopher. Agate is found all over the world including Italy, Egypt, Africa, Germany, Brazil, Mexico, USA, Nepal and India.
