Misakiite
A copper-manganese halide of the atacamite group, approved in 2013 and named for Japan's Sadamisaki (Misaki) peninsula.
Intro adapted from Wikipedia (CC BY-SA).
Misakiite is an IMA-recognized mineral species in the halide class, with the chemical formula Cu₃Mn(OH)₆Cl₂.
It crystallizes in the hexagonal crystal system (space group P-3m1). It is a member of the Atacamite structural group.
Key properties: Mohs hardness 3.42; specific gravity 3.42; Vitreous luster; optically uniaxial.
IMA symbol Msk, IMA status: approved, named in 2013.
A secondary mineral formed by reaction between seawater and primary ore minerals (hausmannite, tephroite, alleghanyite, rhodonite, rhodochrosite, copper, chalcocite) in greenschist facies, metamorphosed.
It is found associated with Cuprite, kutnohorite, malachite, chrysocolla, iyoite.
The name refers to the Sea of Misaki, located near the Sadamisaki Peninsula, Japan.