Carbokentbrooksite 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, Carbokentbrooksite, http://www.mindat.org/min-25674.html with formula (Na, □)₁₂(Na,Ce)₃Ca₆Mn₃Zr₃NbSiO(Si₉O₂₇)₂(Si₃O₉)₂(OH)₃(CO₃)^.H₂O.Khomyakov, A.P., Dusmatov, V.D., Ferraris, G., Gula, A., Ivaldi, G., and Nechelyustov, G.N., 2003: Zirsilite-(Ce), (Na,[])₁₂(Ce,Na)₃Ca₆Mn₃Zr₃Nb(Si₂₅O₇₃)(OH)₃(CO₃)•H2O, and carbokentbrooksite (Na,[])₁₂(Na,Ce)₃Ca₆Mn₃Zr₃Nb(Si₂₅O₇₃)(OH)₃(CO₃)•H₂O - two new eudialyte-group minerals from the Dara-i-Pioz alkaline massif, Tajikistan. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva 132(5), 40–51 (in Russian, with English abstract); in: Jambor, J.I, and Roberts, A.C., 2004: New mineral names. American Mineralogist 89(11-12), 1826-1834 The original formula was extended to show the presence of cyclic silicate groups and silicon at the M4 site, according to the nomenclature of eudialyte group.Johnsen, O., Ferraris, G., Gault, R.A., Grice, D.G., Kampf, A.R., and Pekov, I.V., 2003. The nomenclature of eudialyte-group minerals. The Canadian Mineralogist 41, 785-794 Carbokenbrooksite characterizes in being carbonate-rich (the other eudialyte-group species with essential carbonate are

zirsilite-(Ce) Zirsilite-(Ce) is a very rare mineral of the eudialyte group, with formula .Mindat, Zirsilite-(Ce), http://www.mindat.org/min-25674.htmlKhomyakov, A.P., Dusmatov, V.D., Ferraris, G., Gula, A., Ivaldi, G., and Nechelyustov, G.N., 2003: Zirsilite-(C ...

golyshevite Golyshevite is a rare mineral of the eudialyte group,Mindat, Golyshevite, http://www.mindat.org/min-27418.html with the formula Na10Ca3Ca6Zr3Fe2SiNb(Si3O9)2(Si9O27)2CO3(OH)3•H2O. The original formula was extended to show both the presence of cyc ...

, and

mogovidite Mogovidite is a very rare mineral of the eudialyte group, with formula .Chukanov, N.V., Moiseyev, M.M., Rastsvetayeva, R.K., Rozenberg, K.A., and Zadov, A.E., 2005. Golyshevite (Na,Ca)10Ca9(Fe3+,Fe2+)2Zr3NbSi25O72(CO3)(OH)3·H2O, and Mogovidite, N ...

). It is also sodium rich, being sodium equivalent of

, with which it is intimately associated.

Occurrence and association

Carbokentbrooksite and zirsilite-(Ce) are found as replacements of grains and crystals of eudialyte. They occur in pegmatites of Darai-Pioz alkaline massif, Tajikistan - a locality known for many rare minerals. The minerals are associated with aegirine, ekanite, microcline,

polylithionite Lepidolite is a lilac-gray or rose-colored member of the mica group of minerals with chemical formula . It is the most abundant lithium-bearing mineral and is a secondary source of this metal. It is the major source of the alkali metal rubidium. ...

, quartz,

stillwellite-(Ce) Stillwellite-(Ce) is a rare-earth boro-silicate mineral with chemical formula . Location It occurs as a metasomatic replacement of metamorphosed limestones in the Mary Kathleen mine, Australia and in alkalic pegmatites associated with syenite in ...

(silicates), pyrochlore-group mineral, fluorite,

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 ...

, and

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It cryst ...

Notes on chemistry

Beside the elements given in the formula, carbokentbrooksite contains admixtures of lanthanum,

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

, neodymium, iron, yttrium, titanium, potassium, chlorine, and praseodymium. Carbokentbrooksite and zirsilite-(Ce) are chemically similar.

Notes on structure

Carbokentbrooksite is isostructural with kentbrooksite.

References

Cyclosilicates Sodium minerals Calcium minerals Manganese minerals Zirconium minerals Niobium minerals Trigonal minerals Minerals in space group 160 {{silicate-mineral-stub