Agate is a kind of quartz and it is a mineral. Agate can come in many different kinds and colors. Agate deposits are primarily found in large rocks such as boulders. They take ~50 million years to form. It is characterized by colored band patterns inside various rocks. Often, agates are also accompanied by Amethyst deposits inside.
|Color||White to grey, light blue, orange to red, black.|
|Crystal habit||Cryptocrystalline silica|
|Crystal system||Rhombohedral Microcrystalline|
|Fracture||Conchoidal with very sharp edges.|
|Mohs scale hardness||7|
|Birefringence||up to +0.004 (B-G)|
- Streeter, Edwin W. (2014-07-07). Semi-Precious Stones - A Historical Article on Agate, Amber, Amethyst and Many Other Varieties of Gemstones. Read Books Ltd. ISBN 978-1-4733-9436-0.