Raslakite is a 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 ...

with the chemical formula . This formula is based on the original one, and is extended to show the presence of cyclic silicate groups. The additional silicon and oxygen shown in separation from the cyclic groups (in parentheses) are in fact connected with two 9-fold rings.Mindat, Raslakite, http://www.mindat.org/min-25687.html The mineral has lowered symmetry (space group ''R''3, instead of more specific for the group ''R''3''m'' one),Chukanov, N.V., Pekov, I.V., Zadov, A.E., Korovushkin, V.V., Ekimenkova, I.A., and Rastsvetaeva, R.K., 2003: Ikranite, and raslakite -new eudialyte-group minerals from the Lovozero massif, Kola Peninsula. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva 132(5), 22–33 (in Russian, with English abstract) similarly to some other eudialyte-group members:

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 ...

, labyrinthite, oneillite and

voronkovite Voronkovite is a very rare mineralMindat, Voronkovite, http://www.mindat.org/min-32199.html of the eudialyte group with the chemical formula .Khomyakov, A.P., Nechelyustov, G.N., and Rastsvetaeva, R.K., 2010, Voronkovite, , a new mineral species of ...

. The specific feature of raslakite is, among others, the presence of sodium and zirconium at the M2 site. Raslakite was named after Raslak Cirques located nearby the type locality.

Occurrence and association

Raslakite was discovered, together with

ikranite Ikranite is a member of the eudialyte group, named after the Shubinov Institute of Crystallography of the Russian Academy of Sciences. It is a cyclosilicate mineral that shows trigonal symmetry with the space group ''R''3''m'', and is often seen ...

, in peralkaline pegmatites of the Mt. Karnasurt,

Lovozero massif The Lovozero Massif (, ''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 Peninsula in Russia, between Lovozero and ...

, Kola Peninsula, Russia. Raslakite is associated with

aegirine Aegirine is a member of the clinopyroxene group of inosilicate minerals. It is the sodium endmember of the aegirine– augite series. It has the chemical formula NaFeSi2O6, in which the iron is present as the ion Fe3+. In the aegirine–augite se ...

, fluorcaphite, kazakovite, lamprophyllite,

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 s ...

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 pegmatit ...

, and terskite.

Notes on chemistry

Beside main elements given in the formula, raslakite contains some

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

strontium Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to ...

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

cerium Cerium is a chemical element; it has Chemical symbol, symbol Ce and atomic number 58. It is a hardness, soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it ...

titanium Titanium is a chemical element; it has 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 ...

, and

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

, with minor amounts of

lanthanum Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements bet ...

and

hafnium Hafnium is a chemical element; it has symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dm ...

Notes on crystal structure

The M(1) site in raslakite is split into two sub-sites, where Fe and Ca are located. The M(2) site is occupied by sodium, manganese (both with coordination number 5), and zirconium (tetrahedral coordination).

References

Cyclosilicates Sodium minerals Calcium minerals Iron minerals Zirconium minerals Niobium minerals Trigonal minerals Minerals in space group 146 Minerals described in 2002 {{silicate-mineral-stub