Outstanding black crystals of the very rare Ni-Mn oxide mineral ernienickelite from the type locality in Western Australia (SM7 Pit, Siberia Goldfield, Kalgoorlie-Boulder Shire, Western Australia, Australia) in a matrix of colorless drusy contrasting quartz. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Ernienickelite
Ernienickelite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula NiMn⁴⁺₃O₇·3H₂O.
It crystallizes in the hexagonal crystal system (space group R-3).
Key properties: Mohs hardness 2; specific gravity 3.84; Yellow-brown streak; Metallic, submetallic to vitreous luster; optically uniaxial.
IMA symbol Enk, IMA status: approved, named in 1993.
Found in an intensely laterized ultramafic intrusion (Siberia, Western Australia); in the weathering zone of ultramafic rocks (Kamennyy Kobchik deposit, Russia).
It is found associated with Chalcedonic quartz, magnesite, serpentine, nimite, nontronite, goethite, nickel-rich clay minerals (Siberia, Western Australia); asbolane, lithiophorite.
In honor of Dr. Ernest Henry Nickel (1925–), Canadian-Australian mineralogist with the C.S.I.R.O., Perth, Australia.