< Editing Internet Texts < Gemstones 
Agate
The stone was named after the river Achates, where colorful agates were obtained in the ancient times. It is a microcrystalline and cryptocrystalline variety of the quartz group (crystals are visible only through microscopic examination), usually translucent in thin slices, otherwise opaque. The beauty of its stripey appearance can be highlighted by cutting it en cabochon.
Agate
Basic properties
| Composition | SiO2 |
| Class | Oxydes and hydroxydes |
| Crystal system | Trigonal |
| Mohs' hardness | 7 |
| Fracture | Conchoidal |
| Cleavage | None |
| Lustre | Glassy |
| Streak | White |
| Localities | Brazil, Uruguay (Artigas), Germany (Rochlitz), India (Gujarat), Madagascar, Mexico, USA (Florida) |
This article is issued from Wikiversity. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.