Leifite is a rare tectosilicate mineral that belongs to the leifite group. It was first discovered in 1915 in the Narssârssuk pegmatite of the Ilímaussaq intrusive complex in Greenland. The mineral is named in honor of Leif Erikson, the Norse explorer who is credited with being the first European to reach North America.
Chemical and Physical Properties
Leifite has the chemical formula $NaNa_2(Si,Al,Be)7O{14}(OH,F)$. It is characterized by its content of beryllium, sodium, and aluminum. The mineral typically occurs as colorless, white, or pale-tinted crystals. It possesses a vitreous luster and a white streak.
On the Mohs scale of mineral hardness, leifite ranks approximately at a 6. It has a trigonal crystal system and often forms in prismatic or needle-like (acicular) habits. Its density is approximately 2.56 to 2.59 g/cm³.
Geological Occurrence
Leifite is primarily found in highly alkaline igneous rocks, specifically within alkaline pegmatites. It is often associated with other minerals such as microcline, albite, aegirine, and various rare-earth element minerals.
While its type locality is in Greenland, leifite has also been documented in other significant geological sites, most notably the Poudrette quarry at Mont Saint-Hilaire in Quebec, Canada, and in parts of the Lovozero Massif in the Kola Peninsula, Russia.
Related Minerals
Leifite is the namesake of the leifite group, which includes other chemically similar minerals such as eirikite ($KNa_2(Si,Al,Be)7O{14}(OH,F)$), which is the potassium-dominant analogue of leifite. The structural framework of these minerals consists of a three-dimensional network of tetrahedra, classifying them as tectosilicates.
