|Rock Corner - Agate|
|Agate is classified as a species of Chalcedony. There are many different varieties, which are given descriptive names based on the design or structure of the agate layers. For example blue lace agate, eye agate, moss agate, scenic agate and many others.
It is a very popular ornamental stone and the layering of colours makes it particularly suitable for the carving of cameos. The area of Idar-Oberstein in Germany is famous for carving agate. Local deposits that spurred the growth of the industry are now largely worked out, so it is imported from S.America The stone can also be dyed, with softer bands absorbing more colour than the less porous areas. This treatment is not detectable by the naked eye unless an unnatural shade has been used.
The hardness is 6.5 to 7.5. It is found in the form of nodules in all colours, some stones are even nearly transparent. If the inside of a nodule is filled it is termed a geode. If there is a hollow centre and crystals it is known as a druse.
The name supposedly derives from the River Achates in Sicily.
The most important deposits today are in the south of Brazil, and northern Uraguay. There are many other areas where it is found too, including Australia, China, India, Madagascar, Mexico, Mongolia, Namibia, Wyoming and Montana.
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