Dark red crystal aggregates of the rare mineral norrishite from the type locality in NSW, Australia: Hoskins Mine, Grenfell, New South Wales, Australia. — Photo: David Hospital · CC BY-SA 4.0
Norrishite
Norrishite is an IMA-recognized mineral species in the silicate class, with the chemical formula KLiMn³⁺₂Si₄O₁₀O₂.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Mica structural group.
Key properties: Mohs hardness 2.5; specific gravity 3.264; Vitreous luster; optically biaxial.
IMA symbol Nrr, IMA status: approved, named in 1989.
A ma jor to minor component of manganiferous schists, formed through metamorphism of a stratiform manganese deposit.
It is found associated with Manganoan-alkalic amphibole, manganoan-alkalic clinopyroxene, manganoan pectolite-s¶erandite, braunite, calcium carbonates, barium carbonates, albite.
In honor of Dr. Keith Norrish of the Division of Soils, Commonwealth Scientific and Industrial Research Organization, Australia. All rights reserved. No par t of t his publication may b e reproduced.