White crystals of the very rare Mn-Mg phosphate mineral lun'okite from the TL in Russia (Vasin-Myl'k Mountain, Voron'i Tundry, Murmansk Oblast, Russian Federation) and associated to brown mitridatite. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Lun'okite
Lun'okite is an IMA-recognized mineral species in the phosphate class, with the chemical formula MgMn²⁺Al(PO₄)₂(OH)·4H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbca). It is a member of the Overite structural group.
Key properties: Mohs hardness 3–4; specific gravity 2.66; optically biaxial.
IMA symbol Lun, IMA status: approved, named in 1982.
Found in fractures and on crusts of mitridatite in granite pegmatites.
It is found associated with Eosphorite, laueite, kingsmountite, fairfieldite, mitridatite.
The name refers to the Lun’ok River, nearby Mt. Vasin-Myl’k, Russia.