Labyrinthite is a very rare mineral of the

eudialyte group Eudialyte group is a group of complex trigonal zircono- and, more rarely, titanosilicate minerals with general formula (1)N(2)N(3)N(4)N(5)sub>3 (1a)M(1b)sub>3M(2)3M(4)Z3 i24O72'4X2, where N(1) and N(2) and N(3) and N(5) = Na+ and more rarely H3 ...

.Mindat, http://www.mindat.org/min-27420.html When compared to other species in the group, its structure is extremely complex - with over 100 sites and about 800 cations and anions - hence its name, with its complexity expressed in its chemical formula .Khomyakov, A.P., Nechelyustov, G.N., and Rastsvetaeva, R.K., 2006. Labyrinthite , a new mineral with a modular eudialyte-like structure from Khibiny Alkaline Massif, Kola Peninsula, Russia. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva 135(2), 38-49 The formula is simplified as it does not show the presence of cyclic silicate groups. Complexity of the structure results in symmetry lowering (likely due to ordering of cations) from the typical centrosymmetrical group to ''R''3 space group. Other eudialyte-group representatives with such symmetry lowering include

aqualite Aqualite is a very rare mineral of the eudialyte group, with formula (H3O)8(Na,K,Sr)5Ca6Zr3SiSi(Si24O66)(OH)9Cl.Khomyakov, A. P., Nechelyustov, G. N., and Rastsvetaeva, R. K., 2007: Aqualite, a new mineral species of the eudialyte group from the In ...

oneillite Oneillite is a rare mineral of the eudialyte group with the chemical formula .Mindat, Oneillite, http://www.mindat.org/min-11029.htmlJohnsen, O., Grice, J.D., and Gault, R.A., 1999. Oneillite: a new Ca-deficient and ''REE''-rich member of the eud ...

, raslakite, voronkovite. Labyrinthite is the second dual-nature (both zircono- and titanosilicate) representative of the group after dualiteKhomyakov, A.P., Nechelyustov, G.N., and Rastsvetaeva, R.K., 2009: Dualite, , a new zircono-titanosilicate with a modular eudialyte-like structure from the Lovozero alkaline Pluton, Kola Peninsula, Russia. Geology of Ore Deposits 50(7), 574-582 and third with essential

titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

after dualite and alluaivite.

Occurrence and association

Labyrinthite was discovered in hyperagpaitic (ultra-alkaline) pegmatite at Mt. Nyorkpakhk,

Khibiny massif The Khibiny Mountains (russian: Хиби́ны ; sjd, Umptek) is one of the two main mountain ranges of the Kola Peninsula, Russia, within the Arctic Circle, located between Imandra and Umbozero lakes. The range is also known as Khibiny Massif, K ...

, Kola Peninsula, Russia, where it represents a late-stage mineral. It coexists with aegirine, alkaline

amphibole Amphibole () is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is A ...

lamprophyllite Lamprophyllite (named for its lustrous cleavage) is a rare, but widespread mineral Ti-silicate mineral usually found in intrusive agpasitic igneous rocks. Yellow, reddish brown, Vitreous, Pearly. Lamprophyllite formula is (Sr,Ba,K,Na)2Na(Na,Fe, ...

, lomonosovite, potassium

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 ...

, pectolite,

sodalite Sodalite ( ) is a tectosilicate mineral with the formula , with royal blue varieties widely used as an wikt:ornamental, ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite i ...

, and

villiaumite Villiaumite is a rare halide mineral composed of sodium fluoride, Na F. It is very soluble in water and some specimens fluoresce under long and short wave ultraviolet light. It has a Mohs hardness of 2.5 and is usually red, pink, or orange in col ...

Notes on chemistry

Beside that given in the formula, other elements substituting the main ones in labyrinthite are

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...

, and

cerium Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the +3 o ...

Notes on crystal structure

Labyrinthite is two-modular - its structure contains alluaivite-like and eudialyte-like module. The framework of labyrinthite is 24-layered. It also characterize in doubled ''c'' unit cell parameter.

Occurrence and association

Notes on chemistry

Notes on crystal structure

References

Further reading