- Ilvaite
Ilvaite is a sorosilicate of
iron andcalcium with formula: CaFe2+2Fe3+Si2O7O(OH). Bothmanganese andmagnesium substitute in the structure. Ilvaite crystallizes in theorthorhombic system in black prismatic crystals and columnar masses. It is black to brownish black to gray and opaque. It has aMohs hardness of 5.5 to 6 and aspecific gravity of 3.8 to 4.1. Ilvaite is structurally related tolawsonite .It occurs in contact metamorphic rocks and
skarn ore deposits. It also occurs less commonly insyenite s.Ilvaite was first described in 1811 on the island of
Elba and the name ilvaite from theLatin name "ilva" of the island. Sometimes referred to as YeniteReferences
* [http://webmineral.com/data/Ilvaite.shtml Webmineral]
* [http://mineral.galleries.com/minerals/silicate/ilvaite/ilvaite.htm Mineral galleries]
* [http://www.mindat.org/show.php?id=2016&ld=1&pho= Mindat w/ locations]
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