| Annabergite | |
|---|---|
 Annabergite (green) from Lavrion, Greece | |
| General | |
| Category | Arsenate minerals |
| Formula (repeating unit) | Ni3(AsO4)2·8H2O |
| IMA symbol | Anb[1] |
| Strunz classification | 8.CE.40 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/m |
| Unit cell | a = 10.179(2), b = 13.309(3) c = 4.725(1) [Å]; β = 105(1)°; Z = 2 |
| Identification | |
| Color | Apple-green, pale green, pale rose or pale pink, white, gray; may be zoned |
| Crystal habit | Usually as fibrous veinlets, crystalline crusts, or earthy; rare as well formed crystals |
| Cleavage | Perfect on {010}, indistinct on {100} and {102} |
| Tenacity | Sectile |
| Mohs scale hardness | 1.5–2.5 |
| Luster | Subadamantine, pearly on cleavages, may be dull or earthy |
| Streak | Pale green to white |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 3.07 |
| Optical properties | Biaxial (−) |
| Refractive index | nα = 1.622 nβ = 1.658 nγ = 1.687 |
| Birefringence | δ = 0.065 |
| 2V angle | Measured: 84° |
| References | [2][3][4] |
Annabergite is an arsenate mineral consisting of a hydrous nickel arsenate. It is considered a member of the vivianite group and known for its ability to form crystals in a characteristic apple-green color.
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Handbook of Mineralogy
- ^ Mindat.org
- ^ Webmineral data