Pinkish white crystals of the rare zirconium mineral umbite named after the Lake Umb, 20km east of the type occurrence in Vuonnemiok River Valley (Khibiny Massif, Murmansk Oblast, Russian Federation). Ex.DrHartel collection. — Photo: David Hospital · CC BY-SA 4.0
Umbite
A potassium zirconosilicate named for Lake Umb on the Kola Peninsula.
Intro adapted from Wikipedia (CC BY-SA).
Umbite is an IMA-recognized mineral species in the silicate class, with the chemical formula K₂ZrSi₃O₉·H₂O.
It crystallizes in the orthorhombic crystal system (space group P2_12_12_1). It is a member of the Umbite structural group.
Key properties: Mohs hardness 4.5; specific gravity 2.79; Vitreous luster; optically biaxial.
IMA symbol Umb, IMA status: approved, named in 1982.
Found in pegmatite in a differentiated alkalic massif.
It is found associated with Kostylevite, wadeite, eudialyte, potassic feldspar, aegirine.
The name refers to Lake Umbozero, which separates the Khibiny massif from the Lovozero massif, Kola Peninsula, Russia.