Editing Internet Texts/Gemstones/Andradite
Andradite
[edit | edit source]Andradite is a species of the garnet group. It was named after José Bonifácio de Andrada e Silva (1763-1838), Brazilian politician and mineralogist.
The most valuable variety of andradite is demantoid, also called Uralian emerald. What makes it special are inclusions of actinolite, referred to as horsetail inclusions because of the white or golden color and thread-like shape.[1]
Basic properties
[edit | edit source]| Composition | Ca3Fe2(SiO4)3 |
| Class | Silicates (Neosilicates) |
| Crystal system | Cubic |
| Mohs' hardness | 6,5-7 |
| Fracture | Conchoidal |
| Cleavage | None |
| Lustre | Glassy to adamantine |
| Streak | White |
| Localities | Russia, Italy, Switzerland, USA, China, Namibia |
References
[edit | edit source]- ↑ Minerały i kamienie szlachetne by RBA Collecionables, S.A., ISBN 978-83-7813-150-2, 2012.