zirsilite-(Ce)

{{Short description|Rare mineral of the eudialyte group}}

{{infobox mineral

| name = Zirsilite-(Ce)

| category = Cyclosilicate

| image = Zirsilite-(Ce)-830936.jpg

| imagesize =

| alt =

| caption =

| formula = {{chem2|(Na,□)12(Ce,Na)3Ca6Mn3Zr3Nb(Si25O73)(OH)3(CO3)*H2O}} (original form)

| IMAsymbol = Zir-Ce{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| strunz = 9.CO.10

| dana = 64.1.5

| system = Trigonal

| class = Ditrigonal pyramidal (3m)
H-M symbol: (3m)

| symmetry = R3m

| unit cell = a = 14.25, c = 30.08 [Å] (approximated); Z = 3

| color = Creamy white

| colour =

| habit = rhombohedra (rims of zoned crystals)

| twinning =

| cleavage = None

| fracture = Conchoidal

| tenacity = Brittle

| mohs = 5

| luster = Vitreous

| streak = White

| diaphaneity = Transparent

| gravity =

| density = 3.15 (measured)

| polish =

| opticalprop = Uniaxial (−)

| refractive = nω = 1.65, nε = 1.64 (approximated)

| birefringence =

| pleochroism = None

| 2V =

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| fluorescence = No

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}}

Zirsilite-(Ce) is a very rare mineral of the eudialyte group, with formula {{chem2|(Na,□)12(Ce,Na)3Ca6Mn3Zr3NbSi(Si9O27)2(Si3O9)2O(OH)3(CO3)*H2O}}.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-(Ce), {{chem2|(Na,□)12(Ce,Na)3Ca6Mn3Zr3Nb(Si25O73)(OH)3(CO3)*H2O}}, and carbokentbrooksite {{chem2|(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 the presence of silicon at the M4 site, according to the nomenclature of the 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 Zirsilite-(Ce) differs from carbokentbrooksite in cerium-dominance over sodium only. Both minerals are intimately associated. The only other currently known representative of the eudialyte group having rare earth elements (in particular cerium, as suggested by the "-Ce)" Levinson suffix in the nameHatert, F., Mills, S.J., Pasero, M., and Williams, P.A., 2013. CNMNC guidelines for the use of suffixes and prefixes in mineral nomenclature, and for the preservation of historical names. European Journal of Mineralogy 25, 113–115) in dominance is johnsenite-(Ce).