White crystals of the very rare mineral denisovite from the type locality (Eveslogchorr Mountain, Khibiny Massif, Kola, Russian Federation) and only one of the three known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Denisovite
Denisovite is an IMA-recognized mineral species in the silicate class, with the chemical formula KCa₂Si₃O₈F.
It crystallizes in the monoclinic crystal system.
Key properties: Mohs hardness 4–5; specific gravity 2.76; Pearly to silky luster; optically biaxial.
IMA symbol Dnv, IMA status: approved, named in 1982.
Found in nepheline syenite in a differentiated alkalic massif (Khibiny massif, Russia).
It is found associated with Nepheline, potassic feldspar, aegirine, fluorite, apatite, biotite, yuksporite (Khibiny massif, Russia): aegirine, kalsilite, feldspar (Murun massif, Russia).
The mineral was named to honor Aleksander Petrovich Denisov (1918–1972), Russian specialist in X-ray investigations of minerals, of the Kola Scientific Center, Ruisia.