2.8 x 2.4 x 1.8 cm. Kornite (now potassic-mangani-leakeite) is an extremely rare sodium amphiboles species that is only found in two localities in the world. This piece just happens to be from the type locality for the species, the Wessels Mine in South Africa. This mineral was originially named kornite (for the German geologist Hermann Korn), but was discredited in the 2012 amphibole nomenclature and the mineral renamed potassic-mangani-leakeite. Dark red to brownish "kornite" can be seen associated with dark reddish-black colored prismatic manganvesuvianite on matrix. From the collection of Paolo Matioli. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Potassic-mangani-leakeite
Potassic-mangani-leakeite is an IMA-recognized mineral species in the silicate class, with the chemical formula KNa₂(Mg₂Mn³⁺₂Li)Si₈O₂₂(OH)₂.
It is a member of the Amphibole structural group.
IMA symbol Pmlk, IMA status: approved, named in 1992.