Ziesite
| Ziesite | |
|---|---|
| General | |
| Category | Vanadate mineral |
| Formula (repeating unit) | β-Cu2V2O7 |
| Strunz classification | 8.FA.10 |
| Crystal system | Monoclinic |
| Unit cell |
a = 7.68 Å, b = 8 Å c = 10.09 Å; β = 110.27°; Z = 2 |
| Identification | |
| Color | Black; reddish brown to dark reddish brown in transmitted light; white in reflected light |
| Crystal habit | Anhedral crystals and incrustations |
| Crystal symmetry |
Monoclinic - prismatic H-M symbol: (2/m) Space group: A2/a |
| Cleavage | None |
| Luster | Metallic |
| Streak | Red brown |
| Diaphaneity | Opaque |
| Specific gravity | 3.86 |
| Optical properties | Biaxial |
| Refractive index | 2.055 |
| References | [1][2][3] |
Ziesite is a copper vanadate mineral with formula: β-Cu2V2O7. It was discovered in 1980 as monoclinic crystals occurring as volcanic sublimates around fumaroles in the crater of the Izalco Volcano, El Salvador. It is named after Emmanuel G. Zies (1883–1981), an American geochemist who studied Izalco in the 1930s.
Closely related is blossite, also a copper vanadate with formula of α-Cu2V2O7. It forms orthorhombic crystals. Blossite was also first described for specimens from the Izalco volcano.
Ziesite and blossite are polymorphs, different crystal structure for the same chemical composition and are quite similar in physical properties.
Associated minerals include stoiberite, shcherbinaite, bannermanite, fingerite, mcbirneyite, blossite, chalcocyanite and chalcanthite.[1]