- Kornerupine
Kornerupine is a rare boro-silicate mineral with formula: (Mg,Fe2+)4(Al,Fe3+)6(SiO4,BO4)5(O,OH)2. It crystallizes in the
orthorhombic - dipyramidalcrystal system as brown, green, yellow to colorless slender tourmaline like prisms or in massive fibrous forms. It has aMohs hardness of 7 and aspecific gravity of 3.3 to 3.34. Its indices of refraction are nα=1.660 - 1.671, nβ=1.673 - 1.683 and nγ=1.674 - 1.684.It occurs In boron-rich
volcanic andsedimentary rocks which have undergone high grade metamorphism. It is also found in metamorphosedanorthosite complexes.Kornerupine is valued as a
gemstone when it is found in translucent green to yellow shades. The emerald green varieties are especially sought after.It was first described in 1887 for an occurrence in Fiskernaes in SW
Greenland . It was named in honor of the Danish geologist, Andreas Nikolaus Kornerup (1857-1883).References
* [http://rruff.geo.arizona.edu/doclib/hom/kornerupine.pdf Mineral data publishing 2001 (PDF)]
* [http://webmineral.com/data/Kornerupine.shtml Webmineral data]
* [http://www.mindat.org/min-2254.html Mindat with locality data]
* [http://mineral.galleries.com/minerals/silicate/kornerup/kornerup.htm Mineral galleries]
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