Manganokaskasite
Manganokaskasite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Mo,Nb)S₂·(Mn₁₋ₓAlₓ)(OH)₂₊ₓ.
It crystallizes in the hexagonal crystal system. It is a member of the Valleriite structural group.
Key properties: Mohs hardness 1; specific gravity 4.09; Black streak; Metallic. Anisotropism: Strong luster.
IMA symbol Mkks, IMA status: approved, named in 2013.
Of hydrothermal origin in fenites formed by a peralkaline fluid, as a source of Nb, reacting with a xenolith of alumina-rich metamorphic rocks (metapelites) in agpaitic nepheline syenite.
It is found associated with Orthoclase, anorthoclase, nepheline, fluorophlogopite, corundum, pyrrhotite, pyrite, rutile, monazite-(Ce), graphite, edgarite, molybdenite, tungstenite.
As the manganese analog of kaskaite.