Editing Internet Texts/Gemstones/Agate
Agate
editThe 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.
Basic properties
edit| 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) |