Wiluite (original) (raw)

A valid IMA mineral species

About WiluiteHide

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Formula:

Ca19MgAl4(Al,Mg)8(B,◻)4◻[Si2O7]4[(SiO4)10]O(O,OH)9

The formula is a partial simplification of the full structural formula. The large (VII-IX)-coordinated (X4)2(X3)8(X2)8(X1) sites are here combined (e.g. Ca19) and are typically filled with Ca, although other large cations such as the REE may be present. The square-pyramidal Y1 site can host a variety of M2+ and M3+ ions and is the basis for the distinction of several species. The VI-coordinated Y2 site typically is filled with Al, whereas the also VI-coordinated Y3 site may contain Al, Mg, and other cations of similar charge and size. The tetrahedral T1 site is typically vacant but may contain B (less commonly Al); the trigonal T2 site is also typically vacant but may also contain B. Some of the (SiO4) may be replaced by (H4O4), akin to the Si4+ ↔︎ 4H+ hydrogarnet substitution. Among the oxygen that are not part of the silica tetrahedra, there are eight "O11" that typically occur as OH, two "O10" that are typically O & OH or OH & OH (the latter arrangement notably when Y1 is an M2+ cation). There may also be up to three "O12" that in most vesuvianite-group minerals are absent (and are not included here), but may be present particularly when T1 is occupied.

With increased filling of the T2 site by B, various charge balance mechanisms involving either increased O for OH in the "O11" position and/or increased M2+ for M3+ substitution in the Y3 site are necessary (see idealized formula for full T2 occupancy by B). In lieu of an explicitly defined "end-member" wiluite, more generic representations of site fillings are retained here, pending newer data.

Crystal System:

Tetragonal

Name:

Named after the discovery locality, Wilui River basin, Sakha Republic (Yakutia), Russia.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:7367:3

a013fc19-306f-4f38-89cd-b8f2892be54e

IMA Classification of WiluiteHide

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IMA Formula:

Ca19(Al,Mg)13(B,◻,Al)5(SiO4)10(Si2O7)4(O,OH)10

Type description reference:

Groat, L. A., Hawthorne, F. C., Erit, T. S., Grice, J. D. (1998) Wiluite, Ca19(Al,Mg,Fe,Ti)13(B,Al,◻)5Si18O68(O,OH)10, a new mineral species isostructural with vesuvianite, from the Sakha Republic, Russian Federation. The Canadian Mineralogist, 36 (5). 1301-1304

Classification of WiluiteHide

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9.BG.35

9 : SILICATES (Germanates)
B : Sorosilicates
G : Sorosilicates with mixed SiO4 and Si2O7 groups; cations in octahedral [6] and greater coordination

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Pronunciation of WiluiteHide

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Pronunciation:

Physical Properties of WiluiteHide

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Transparency:

Transparent, Translucent

Cleavage:

Poor/Indistinct
Poor cleavage on {100}.

Fracture:

Irregular/Uneven

Density:

3.36(3) g/cm3 (Measured) 3.358 g/cm3 (Calculated)

Optical Data of WiluiteHide

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RI values:

_n_ω = 1.721(2) _n_ε = 1.725(2)

δ = 0.004

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Chemistry of WiluiteHide

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Mindat Formula:

Ca19MgAl4(Al,Mg)8(B,◻)4◻[Si2O7]4[(SiO4)10]O(O,OH)9

The formula is a partial simplification of the full structural formula. The large (VII-IX)-coordinated (X4)2(X3)8(X2)8(X1) sites are here combined (e.g. Ca19) and are typically filled with Ca, although other large cations such as the REE may be present. The square-pyramidal Y1 site can host a variety of M2+ and M3+ ions and is the basis for the distinction of several species. The VI-coordinated Y2 site typically is filled with Al, whereas the also VI-coordinated Y3 site may contain Al, Mg, and other cations of similar charge and size. The tetrahedral T1 site is typically vacant but may contain B (less commonly Al); the trigonal T2 site is also typically vacant but may also contain B. Some of the (SiO4) may be replaced by (H4O4), akin to the Si4+ ↔︎ 4H+ hydrogarnet substitution. Among the oxygen that are not part of the silica tetrahedra, there are eight "O11" that typically occur as OH, two "O10" that are typically O & OH or OH & OH (the latter arrangement notably when Y1 is an M2+ cation). There may also be up to three "O12" that in most vesuvianite-group minerals are absent (and are not included here), but may be present particularly when T1 is occupied.

With increased filling of the T2 site by B, various charge balance mechanisms involving either increased O for OH in the "O11" position and/or increased M2+ for M3+ substitution in the Y3 site are necessary (see idealized formula for full T2 occupancy by B). In lieu of an explicitly defined "end-member" wiluite, more generic representations of site fillings are retained here, pending newer data.

Crystallography of WiluiteHide

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Crystal System:

Tetragonal

Class (H-M):

4/m m m _(_4/_m_2/_m_2/m ) - Ditetragonal Dipyramidal

Cell Parameters:

a = 15.716(1) Å, c = 11.704(1) Å

Unit Cell V:

2,890.80 ų (Calculated from Unit Cell)

Comment:

Wiluite from Ariccia, Latium, Italy

Crystal StructureHide

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ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0006057	Wiluite	Bellatreccia F, Camara F, Ottolini L, Della Ventura G, Cibin G, Mottana A (2005) Wiluite from Ariccia, Latium, Italy: Occurrence and crystal structure The Canadian Mineralogist 43 1457-1468		2005	Ariccia, Latium, Italy	0	293

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Type Occurrence of WiluiteHide

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Place of Conservation of Type Material:

Canadian Museum of Nature, Ottawa, Ontario, Canada.

Geological Setting of Type Material:

Reference:

GROAT, L.A., HAWTHORNE, F.C., ERCIT, T.S., and GRICE, J.D. (1998): Wiluite, Ca19(Al,Mg,Fe,Ti)13(B,Al,[])5Si18O68(O,OH)10, a new mineral species isostructural with vesuvianite, from the Sakha Republic, Russian Federation. Canadian Mineralogist 36, 1301-1304.

Synonyms of WiluiteHide

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Other Language Names for WiluiteHide

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Relationship of Wiluite to other SpeciesHide

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Other Members of this group:

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Fluorescence of WiluiteHide

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Other InformationHide

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Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for WiluiteHide

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References for WiluiteHide

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Reference List:

Groat, L. A., Hawthorne, F. C., Erit, T. S., Grice, J. D. (1998) Wiluite, Ca19(Al,Mg,Fe,Ti)13(B,Al,◻)5Si18O68(O,OH)10, a new mineral species isostructural with vesuvianite, from the Sakha Republic, Russian Federation. The Canadian Mineralogist, 36 (5). 1301-1304

Bellatreccia, F., Camara, F., Ottolini, L., Della Ventura, G., Cibin, G., Mottana, A. (2005) Wiluite from Ariccia, Latium, Italy: Occurrence and crystal structure. The Canadian Mineralogist, 43 (5). 1457-1468 doi:10.2113/gscanmin.43.5.1457

Panikorovskii, Taras L., Mazur, Anton S., Bazai, Ayya V., Shilovskikh, Vladimir V., Galuskin, Evgeny V., Chukanov, Nikita V., Rusakov, Vyacheslav S., Zhukov, Yurii M., Avdontseva, Evgenia Yu., Aksenov, Sergey M., Krivovichev, Sergey V. (2017) X-ray diffraction and spectroscopic study of wiluite: implications for the vesuvianite-group nomenclature. Physics and Chemistry of Minerals, 44 (8) 577-593 doi:10.1007/s00269-017-0885-2

Localities for WiluiteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.