Kambaldaite—a new hydrated Ni–Na carbonate mineral from Kambalda, Western Australia

Kambaldaite has the ideal composition Na₂Ni₈(CO₃)₆(OH)₆ · 6H₂O. It is hexagonal, space group P6₃, with a = 10.340Å and c = 6.097Å; Z = 1. Strongest X-ray powder diffraction lines are: 9.03(10)(1010), 4.490(9)(2020), 3.613(4)(2021), 2.681(4)(3031), 2.584(4)(2240), 2.519(4)(2022) and 2.263(4)(2132). The mineral occurs as needles and prismatic crystals elongated along c, as well as cryptocrystalline masses. Uniaxial positive, with ω = 1.65 and ∈ = 1.69. Kambaldaite is emerald green in color, with a pale green streak; in transmitted light it is dichroic with E = emerald green and O = light green. Measured density = 3.18 g/cm³; calculated density of the ideal formula = 3.193 g/cm³. Kambaldaite is a secondary mineral that has been precipitated on fracture surfaces in oxidizing Ni–Fe sulfide ore.