Zaratite
| Zaratite | |
|---|---|
|
Zaratite from Tasmania | |
| General | |
| Category | Carbonates |
| Formula (repeating unit) | Ni3CO3(OH)4·4H2O |
| Strunz classification | 5.DA.70 |
| Crystal system | Isometric (in part amorphous) |
| Unit cell | a = 6.16 Å; Z = 1 |
Zaratite is a bright emerald green and questionable nickel carbonate mineral with formula Ni3CO3(O H)4·4 H2O. Zaratite crystallizes in the isometric crystal system as massive to mammillary encrustations and vein fillings. It has a specific gravity of 2.6 and a Mohs hardness of 3 to 3.5. It has no cleavage and is brittle to conchoidal fracture. The luster is vitreous to greasy.
It is a rare secondary mineral formed by hydration or alteration of the primary nickel and iron bearing minerals, chromite, pentlandite, pyrrhotite, and millerite, during the serpentinization of ultramafic rocks. Hellyerite, NiCO3·6H2O, is a related mineral.
It was found originally in Galicia, Spain in 1851, and named after Spanish diplomat and dramatist Antonio Gil y Zárate (1793–1861).