Leifite is a rare

tectosilicate Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

. Tectosilicates are built on a framework of tetrahedra with

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

at the centre and

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

at the vertices; they include

feldspars Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspa ...

and

zeolites Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These pos ...

, but leifite does not belong in either of these categories. It is a member of the leifite group, which includes telyushenkoite ) and eirikite ). Leifite was discovered in 1915, and named after

Leif Ericson Leif Erikson, Leiv Eiriksson, or Leif Ericson, ; Modern Icelandic: ; Norwegian: ''Leiv Eiriksson'' also known as Leif the Lucky (), was a Norse explorer who is thought to have been the first European to have set foot on continental North ...

who was a Norse explorer who lived around 1000 AD, and was probably the first European to land in North America, nearly 500 years before

Christopher Columbus Christopher Columbus * lij, Cristoffa C(or)ombo * es, link=no, Cristóbal Colón * pt, Cristóvão Colombo * ca, Cristòfor (or ) * la, Christophorus Columbus. (; born between 25 August and 31 October 1451, died 20 May 1506) was a ...

. Eirikite was named in 2007 after

Eirik Raude Erik Thorvaldsson (), known as Erik the Red, was a Norse explorer, described in medieval and Icelandic saga sources as having founded the first settlement in Greenland. He most likely earned the epithet "the Red" due to the color of his hair a ...

, or Erik the Red, (950–1003), who discovered

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

and who was the father of Leif Ericson. The third mineral in the group, telyushenkoite, was discovered in 2001. It was not named after any of Leif Ericson's family members, but after a professor of geology in

Turkmenistan Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the sout ...

Structure

Leifite is a

trigonal In crystallography, the hexagonal crystal family is one of the six crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the trigonal crysta ...

mineral, class 2/m,

space group In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchan ...

Pm1.Canadian Mineralogist (2002)40:183-192 There are 3 formula units in the

unit cell In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessaril ...

(Z = 3), and cell dimensions are 14.4 Å in the a direction and 4.9 Å in the c direction.American Mineralogist (1972) 57:1006Bulletin of the Geological Society of Denmark 20:134 (1970) It contains OH groups, but no

water of crystallization In chemistry, water(s) of crystallization or water(s) of hydration are water molecules that are present inside crystals. Water is often incorporated in the formation of crystals from aqueous solutions. In some contexts, water of crystallization is ...

as was previously assumed.Norsk Geologisk Tidsskrift (1995) 75:243-246 Tetrahedrons of

atoms surrounded by four

atoms link to form six-membered rings stacked along the c direction to form channels, similar to those in

Appearance

Leifite is generally white or colourless, with a white streak and a silky or vitreous

lustre Lustre or Luster may refer to: Places * Luster, Norway, a municipality in Vestlandet, Norway ** Luster (village), a village in the municipality of Luster * Lustre, Montana, an unincorporated community in the United States Entertainment * '' ...

. It occurs as fine needles making up radiating

aggregate Aggregate or aggregates may refer to: Computing and mathematics * collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...

s and rosettes. Individual crystals are deeply striated

hexagonal In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...

prisms that are transparent to translucent.

Physical Properties

The mineral is hard, with Mohs hardness 6, the same as that of

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...

, and

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...

2.6, again like the feldspars. It is brittle, with an uneven to splintery

fracture Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...

Optical Properties

Leifite is uniaxial(+) with

refractive indices In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

n_ω = 1.516 and n_ε = 1.520. The maximum

birefringence Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are said to be birefringent (or birefractive). The birefring ...

δ = 0. 011. Leifite is not

luminescent Luminescence is spontaneous emission of light by a substance not resulting from heat; or "cold light". It is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions or stress on a cryst ...

Occurrence

The type locality is the

Narsaarsuk Narsaarsuk (old spelling: ''Narssârssuk'') is an abandoned settlement on the edge of Bylot Sound in northern Greenland near Thule Air Base. The site of the former settlement is contaminated with plutonium after the 1968 Thule Air Base B-52 crash ...

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...

on the Narsaarsuk Plateau, Igaliku, Narsaq, Kujalleq, Greenland and type material is kept at the

University of Copenhagen The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in ...

, Denmark, and at the

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...

in Washington DC, US. Leifite occurs in cavities in alkali-pegmatite

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

. At

Mont Saint-Hilaire Mont Saint-Hilaire (English: Mount Saint-Hilaire; abe, Wigwômadenizibo; see for other names) is an isolated hill, high, in the Montérégie region of southern Quebec. It is about thirty kilometres east of Montreal, and immediately east of the ...

it occurs as crystals up to 5 cm long and as disk-shaped aggregates and radially fibrous spheres associated with

albite Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. I ...

natrolite Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany. It was named natrolite by Martin Heinrich Klaproth i ...

serandite Serandite is a mineral with formula Na(Mn2+,Ca)2Si3O8(OH). The mineral was discovered in Guinea in 1931 and named for J. M. Sérand. Serandite is generally red, brown, black or colorless. The correct name lacks an accent. Description Serandite i ...

and catapleite. In

it occurs in a pegmatite with

microcline Microcline (KAlSi3O8) is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in granite and pegmatites. Microcline forms during slow ...

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

zinnwaldite Zinnwaldite, K Li Fe Al(Al Si3) O10(O H, F)2, potassium lithium iron aluminium silicate hydroxide fluoride is a silicate mineral in the mica group. The IMA status is as a series between siderophyllite (KFe2Al(Al2Si2)O10(F,OH)2) and polylithion ...

and

acmite Aegirine is a member of the clinopyroxene group of inosilicate minerals. Aegirine is the sodium endmember of the aegirine-augite series. Aegirine has the chemical formula Na Fe Si2 O6 in which the iron is present as Fe3+. In the aegirine-augite ...

. In Russia it occurs in the

Lovozero Massif The Lovozero Massif (russian: Ловозёрские тундры, ''Lovozyorskiye Tundry'', named after the lake in that area – Lake Lovozero; the region is also known as , ''Lovozyorye'') is a mountain range located in the center of the Kola ...

associated with

and

. In Norway it occurs in a

nepheline Nepheline, also called nephelite (), is a rock-forming mineral in the feldspathoid groupa silica-undersaturated aluminosilicate, Na3 K Al4 Si4 O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites ...

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). Some syenites contain larger proport ...

pegmatite on the south eastern part of the island of Vesle Aroya in the

Langesundsfjord The Langesundsfjord (), also known as the Breviksfjord (), is a stretch of fjord from northern Skagerrak, between the islands of Sandøya, Bjørkøya and Siktesøya in Porsgrunn municipality and the mainland of Bamble municipality, in Telemark c ...

District, Oslo Region, as white to colourless fibrous masses and radiating bundles.

References

{{Reflist Silicate minerals Trigonal minerals Minerals in space group 164