Wiluite

{{Infobox mineral

| name = Wiluite

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| image = Wiluite-rh3-48b.jpg

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| caption = Wiluite crystal from the Wilui River, Siberia

| category = Sorosilicates

| formula = {{chem2|Ca19(Al,Mg,Fe,Ti)13(B,Al,[ ])5Si18O68(O,OH)10}}

| IMAsymbol = Wil{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|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}}

| molweight =

| strunz = 9.BG.35

| system = Tetragonal

| class = Ditetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)

| symmetry = P4/nnc

| unit cell = a = 15.716, c = 11.704 [Å]; Z = 2

| color = Dark green

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| habit = Typically as euhedral crystals

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| cleavage = {100} poor

| fracture = Irregular

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| mohs = 6

| luster = Vitreous

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| gravity = 3.36

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| opticalprop = Uniaxial (+)

| refractive = n_ω = 1.721 n_ε = 1.725

| birefringence = δ = 0.004

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| references = [http://webmineral.com/data/Wiluite.shtml Webmineral data][http://www.mindat.org/min-7367.html Mindat with location data]

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Wiluite is a dark green, brownish, or black blocky silicate mineral with the chemical formula {{chem2|Ca19(Al,Mg,Fe,Ti)13(B,Al,[ ])5Si18O68(O,OH)10}}. It has a Mohs hardness of 6 and a specific gravity of 3.36. It has a vitreous lustre, poor cleavage and an irregular brittle fracture. It crystallizes in the tetragonal system and occurs as well-formed crystals with good external form. It is isostructural with the vesuvianite group and is associated with wollastonite and olive-green grossulars (viluites) in a serpentinized skarn.

The minerals that wiluite and viluite refer to have often been confused, and may refer to grossular,[http://www.mindat.org/min-5508.html Viluite] Mindat database[http://www.mindat.org/min-5510.html Wiluite (of Severgin)] Mindat database or wiluite.[http://www.mindat.org/min-7367.html Wiluite] Mindat database[http://www.gemmology.org/pierresnaturelles/wen.html W - Wiluite] World of Gemstones dictionary, accessed online January 25, 2007[http://www.gemmology.org/pierresnaturelles/ven.html V - Viluite] World of Gemstones dictionary, accessed online January 25, 2007

It was discovered in the 1990s and named for the Wilui River region, Sakha Republic (Yakutia), Russia.

Viluite was introduced as a mineral name twice. Von Leonhard used it for a mineral that was considered the same as vesuvianite. However, that material was recently shown to be rich in boron and thus different from vesuvianite. In 1998 that material was named Wiluite. The other author to introduce viluite was Severgin, who used it in reference to what is widely known as grossular, a member of the garnet group.de Fourestier, Jeffrey; Glossary of Mineral Synonyms, Canadian Mineralogist Special Publication 2, Mineralogical Association of Canada, Ottawa, Ontario, 1999, 445 pp. {{ISBN|0921294441}}