Wiluite is a dark green, brownish, or black blocky

silicate mineral Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

with the chemical formula . 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 In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a squar ...

system and occurs as well-formed crystals with good external form. It is isostructural with the

vesuvianite Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuvianite occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism. It was first discovered within ...

group and is associated with

wollastonite Wollastonite is a calcium inosilicate mineral ( Ca Si O3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolomite is subjected to high temperature ...

and olive-green

grossular Grossular is a calcium-aluminium species of the garnet group of minerals. It has the chemical formula of Ca3Al2(SiO4)3 but the calcium may, in part, be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from t ...

s (viluites) in a serpentinized

skarn Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate mineral ...

. The minerals that ''wiluite'' and ''viluite'' refer to have often been confused, and may refer to grossular, or wiluite. It was discovered in the 1990s and named for the Wilui River region, Sakha Republic (Yakutia),

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...

. 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.

References

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External links

*http://hyperphysics.phy-astr.gsu.edu/hbase/minerals/vesuvianite.html *https://www.cs.cmu.edu/~adg/adg-psssimages.html#wilui Sorosilicates Tetragonal minerals Minerals in space group 126