Titanite

Titanite, or spheneFormula: CaTiSiO₅Mohs scale hardness: 5-5,5Specific gravity: 3,48-3,6ТiO₂ - 40,8%Also commonly present are rare earth metals including cerium and yttrium; calcium may be partly replaced by thorium.Titanite occurs as a common accessory mineral in intermediate and felsic igneous rocks and associated pegmatites. It also occurs in metamorphic rocks such as gneiss and schists and skarns. Source localities include: Pakistan; Italy; Russia; China; Brazil; Tujetsch, St. Gothard, Switzerland; Madagascar; Tyrol, Austria; Renfrew County, Ontario, Canada; Sanford, Maine, Gouverneur, Diana, Rossie, Fine, Pitcairn, Brewster, New York and California in the USA.Area of application: Titanite is a source of titanium dioxide, TiO2, used in pigments. As a gemstone, titanite is usually some shade of chartreuse, but can be brown or black. Jewelry use of titanite is limited, both because the stone is uncommon in gem quality and is relatively soft.References

1. https://en.wikipedia.org

2. https://en.wikipedia.org/wiki/Titanite

   1. http://www.mindat.org/min-3977.html

3. https://commons.wikimedia.org/wiki/File:Titanite_crystal_yellow_-_Ochtendung,_Eifel,_Germany.jpg