Leifite Locality: Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire , Rouville RCM, Montérégie , Québec , Canada ( Locality at mindat.org ) Size: 1.8 x 1.5 x 1.4 cm. A superb cluster of translucent, 3-dimensional leifite crystals of the most desirable habit - showing real terminations instead of merging into an acicular mess as some styles do. Ex. Carlton Davis Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Leifite
A rare beryllium-bearing tectosilicate — a framework silicate that fits neither the feldspar nor the zeolite family.
Intro adapted from Wikipedia (CC BY-SA).
Leifite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₇Be₂(Si₁₅Al₃)O₃₉(F,OH)₂.
It crystallizes in the hexagonal crystal system (space group P-3m1). It is a member of the Leifite structural group.
Key properties: Mohs hardness 6; specific gravity 2.57; Silky luster; refractive index 1.518; optically uniaxial.
IMA symbol Lf, IMA status: approved, named in 1915.
Found in pegmatite (Narss^arssuk, Greenland); in a differentiated alkalic massif (Lovozero massif, Russia); in association with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada).
It is found associated with Microcline, aegirine, zinnwaldite, calcite (Narss^arssuk, Greenland); albite, natrolite (Lovozero massif, Russia); rhodochrosite.
The name refers to Leif Ericson, Norse adventurer and discoverer of Greenland in 982.