Villiaumite is a rare halide mineral

Halide mineral

The halide mineral class include those minerals with a dominant halide anion . Complex halide minerals may also have polyatomic anions in addition to or that include halides.Examples include the following:*Halite NaCl*Sylvite KCl...

 composed of sodium fluoride

Sodium fluoride

Sodium fluoride is an inorganic chemical compound with the formula NaF. A colorless solid, it is a source of the fluoride ion in diverse applications. Sodium fluoride is less expensive and less hygroscopic than the related salt potassium fluoride....

, Na

Sodium

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

F

Fluorine

Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...

. It is very soluble in water and some specimens fluoresce under long and short wave ultraviolet

Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 light. It has a Mohs hardness of 2.5 and is usually red, pink, or orange in color. It is toxic to humans and should be handled with care.

Occurrence

It occurs in nepheline syenite

Nepheline syenite

Nephelene syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are also known...

 intrusives and in nepheline syenite pegmatite

Pegmatite

A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....

s. It occurs associated with aegirine

Aegirine

Aegirine is a member of the clinopyroxene group of inosilicates. Aegirine is the sodium endmember of the aegirine-augite series. Aegirine has the chemical formula NaFeSi2O6 in which the iron is present as Fe3+. In the aegirine-augite series the sodium is variably replaced by calcium with iron and...

, sodalite

Sodalite

Sodalite is a rich royal blue mineral widely enjoyed as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent...

, nepheline

Nepheline

Nepheline, also called nephelite , is a feldspathoid: a silica-undersaturated aluminosilicate, Na3KAl4Si4O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites...

, neptunite

Neptunite

Neptunite is a silicate mineral with the formula KNa2Li2Ti2Si8O24. With increasing manganese it forms a series with mangan-neptunite. Watatsumiite is the variety with vanadium replacing the titanium in the formula....

, lamprophyllite, pectolite

Pectolite

Pectolite is a white to gray mineral, NaCa2Si3O8, sodium calcium inosilicate hydroxide. It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses. It has a Mohs hardness of 4.5 to 5 and a specific gravity of 2.7 to 2.9. The gemstone variety, larimar, is a...

, serandite, eudialyte

Eudialyte

Eudialyte, whose name derives from the Greek phrase Εὖ διάλυτος eu dialytos, meaning "well decomposable", is a somewhat rare, red silicate mineral, which forms in alkaline igneous rocks, such as nepheline syenites...

, ussingite

Ussingite

Ussingite is a silicate mineral with formula Na2AlSi3O8.It was named for Niels Viggo Ussing , Copenhagen, Denmark....

, chkalovite and zeolite

Zeolite

Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents. The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that upon rapidly heating the material stilbite, it produced large amounts of steam from water that...

s. It has been reported from Minas Gerais

Minas Gerais

Minas Gerais is one of the 26 states of Brazil, of which it is the second most populous, the third richest, and the fourth largest in area. Minas Gerais is the Brazilian state with the largest number of Presidents of Brazil, the current one, Dilma Rousseff, being one of them. The capital is the...

, Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

; Mont Saint-Hilaire

Mont Saint-Hilaire

Mont Saint-Hilaire , 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 Richelieu River. It is one of the Monteregian Hills...

, Quebec

Quebec

Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

; the Ilimaussaq complex of Greenland

Greenland

Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

; Lake Magadi

Lake Magadi

Lake Magadi is the southernmost lake in the Kenya Rift Valley, lying in a catchment of faulted volcanic rocks, north of Tanzania's Lake Natron. During the dry season, it is 80% covered by soda and is well known for its wading birds, including flamingos....

, Kenya

Kenya

Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

; Windhoek

Windhoek

Windhoek is the capital and largest city of the Republic of Namibia. It is located in central Namibia in the Khomas Highland plateau area, at around above sea level. The 2001 census determined Windhoek's population was 233,529...

 District, Namibia

Namibia

Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

; the Fen Complex

Fen Complex, Norway

The Fen complex in Nome, Telemark, Norway is a region noted for an unusual suite of igneous rocks. Several varieties of carbonatite are present in the area as well as lamprophyre, ijolite and other highly alkalic rocks...

, Telemark

Telemark

is a county in Norway, bordering Vestfold, Buskerud, Hordaland, Rogaland and Aust-Agder. The county administration is in Skien. Until 1919 the county was known as Bratsberg amt.-Location:...

, Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

; the Khibiny

Khibiny Massif

The Khibiny Massif, Khibiny Mountains, Khibinsky Mountains or Khibins, Khibinsky tundras, Khibiny is one of the two main mountain ranges of the Kola Peninsula, Russia, within the Arctic Circle, located between Imandra and Umbozero lakes.The massif is of oval shape of about 1,300 sq.km...

 and Lovozero Massifs, Kola Peninsula

Kola Peninsula

The Kola Peninsula is a peninsula in the far northwest of Russia. Constituting the bulk of the territory of Murmansk Oblast, it lies almost completely to the north of the Arctic Circle and is washed by the Barents Sea in the north and the White Sea in the east and southeast...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

; Porphyry Mountain, Boulder County, Colorado

Boulder County, Colorado

Boulder County is the sixth most populous of the 64 counties of the state of Colorado of the United States. The county seat is Boulder. The most populous municipality in the county and the county seat is the City of Boulder...

 and Point of Rocks Mesa, Colfax County, New Mexico

Colfax County, New Mexico

-2010:Whereas according to the 2010 U.S. Census Bureau:*83.8% White*0.5% Black*1.5% Native American*0.4% Asian*0.1% Native Hawaiian or Pacific Islander*3.6% Two or more races*10.1% Other races*47.2% Hispanic or Latino -2000:...

, USA.

It was first described in 1908 for an occurrence in Los Islands, Guinea

Guinea

Guinea , officially the Republic of Guinea , is a country in West Africa. Formerly known as French Guinea , it is today sometimes called Guinea-Conakry to distinguish it from its neighbour Guinea-Bissau. Guinea is divided into eight administrative regions and subdivided into thirty-three prefectures...

 and named after the French explorer, Maxime Villiaume.