Kambaldaite, NaNi4(CO3)3(OH)3·3H2O, is an extremely rare hydrated sodium nickel carbonate mineral described from gossanous material associated with Kambalda type komatiitic nickel ore deposits at Kambalda, Western Australia, and Widgie Townsite nickel gossan, Widgiemooltha, Western Australia.
Kambaldaite was first described in 1985 from the gossan of the Otter Shoot nickel orebody, Kambalda, during mining of the gossanous material.
- Category: Carbonate minerals
- Formula: NaNi4(CO3)3(OH)33H2O
- Crystal system: Hexagonal
- Crystal class: Pyramidal (6)
Kambaldaite crystallizes in the hexagonal system, is light green to blue and forms drusy to mammillated encrustations on the matrix. It is a rare secondary mineral that can be found in goethite residues that were formed by the oxidation of violarite-pyrite with associated carbonates and saline groundwater.
- Cleavage: None
- Color: Light green, Emerald green.
- Density: 3.18
- Hardness: 3 – Calcite
- Luster: Vitreous (Glassy)
- Streak: light green
Kambaldaite is associated with goethite, malachite, annabergite, gaspeite and magnesite in the nickel sulfide gossans of Kambalda and Widgiemooltha. It is not known from other nickel sulfide gossans within the Yilgarn Craton, potentially due to many of these existing within areas of laterite cover, deeper regolith development or less favorable rainfall conditions.
Kambaldaite is not reported from the Tasmanian or New South Wales nickel carbonate occurrences because it is a supergene carbonate mineral and not a hydrothermal mineral.
Kambaldaite, though in lesser and rarer amount, is also found in the Widgiemooltha nickel gossans, probably discovered there in the early to mid-1990s. It is also reported from the Inn Valley, North Tyrol, Austria, and from Linopolis, Minas Gerais, Brazil.
Association: Gasp´eite, reevesite, aragonite, pyrite, goethite (Kambalda, Western Australia).