- Willemite
Infobox mineral
name = Willemite
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caption = Willemite withfranklinite fromNew Jersey
formula =Zinc silicate (Zn2SiO4)
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color = Blue to Green
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system = Rhombohedral
twinning =
cleavage = {010}, {100} - imperfect
fracture = Uneven, Conchoidal
mohs = 5.5
luster = Vitreous - Resinous
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gravity = 3.9 - 4.2
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other =Willemite is a
zinc silicate (Zn2SiO4) and a minor ore of zinc. It is highlyfluorescent (green) under shortwaveultraviolet light. It occurs in all different colors in daylight, in fibrous masses, solid brown masses ("troostite"), and apple green gemmy masses. Willemite is usually formed as an alteration of previously existingsphalerite ore bodies, and is usually associated with limestone. It occurs in many places, but is best known from Arizona and the world famous zinc, iron, manganese deposits atFranklin Furnace ,New Jersey . It often occurs with redzincite (zinc oxide) andfranklinite (Fe,Mn,Zn)(Fe,Mn)2O4 (an iron rich zinc mineral occurring in sharp black isometric octahedral crystals and masses). Franklinite and zincite are not fluorescent.It was discovered in
1830 and named after William I of the Netherlands.ee also
*
List of minerals
*List of minerals named after people References
* [http://mineral.galleries.com/minerals/silicate/willemit/willemit.htm Mineral galleries]
* [http://www.mindat.org/min-4292.html Mindat]
* [http://webmineral.com/data/Willemite.shtml Webmineral]
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