Molybdenite
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robot Adding: [[eu:Molibdenita]]
{{Infobox mineral
| name = Molybdenite
| category =
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| image = Molybdenite.jpg
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| formula = [[molybdenum]] [[sulfide]]:MoS<sub>2</sub>
| molweight =
| color = Black, lead-silvery gray
| habit = Thin, platy hexagonal crystals terminated by pinacoidal faces, also as tapering six-sided pyramids that can be truncated by the pinacoids. Also massive, lamellar and in small grains in sulfide ore bodies
| system = [[Hexagonal]]; 6/m 2/m 2/m
| twinning =
| cleavage = [0001] Perfect
| fracture = flaky
| mohs = 1 - 1.5
| luster = Metallic
| refractive = Opaque
| opticalprop =
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| pleochroism =
| streak = bluish - gray
| gravity = 4.73
| density =
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| fusibility = Infusible
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| other = Thin cleavage sheets and crystals are flexible, but not elastic. It has a greasy feel and leaves marks on fingers
}}
'''Molybdenite''' is a mineral of [[molybdenum disulfide]], [[molybdenum|Mo]][[sulfur|S]]<sub><small>2</small></sub>. Similar in appearance and feel to [[graphite]], molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of [[sulfide]] atoms. The Mo-S bonds are strong, but the interaction between the sulfur atoms at the top and bottom of separate sandwich-like tri-layers is weak, resulting in easy slippage as well as [[cleavage plane]]s.
Associated minerals include [[pyrite]], [[chalcopyrite]], [[quartz]], [[anhydrite]], [[fluorite]], and [[scheelite]]. Occurs in high temperature [[hydrothermal]] [[ore]] deposits. Important deposits include the disseminated porphyry molybdenum deposit at [[Questa, New Mexico]] and [[Climax, Colorado]]. Molybdenite also occurs in [[porphyry copper]] deposits of [[Arizona]], [[Colorado]], [[Utah]], and [[Mexico]].
The element [[rhenium]] is always present in molybdenite as a substitute for molybdenum usually in the parts per million (ppm) range, but often up to 1-2%. High rhenium content results in a structural variety detectable by [[X-ray diffraction]] techniques. Molybdenite ores are essentially the only source for rhenium. The presence of the [[radioactive isotope]] rhenium-187 and its daughter isotope [[osmium]]-187 provides a useful [[geochronology|geochronologic]] dating technique.
== References and external links ==
{{commonscat|Molybdenite}}
*Dana's Manual of Mineralogy ISBN 0-471-03288-3
*[http://mineral.galleries.com/minerals/sulfides/molybden/molybden.htm Mineralgalleries.com]
*[http://webmineral.com/data/Molybdenite.shtml Webmineral]
*[http://www.mindat.org/min-2746.html Mindat.org]
*[http://www.cnr.colostate.edu/airie/Molybdenite.htm Molybdenite Dating]
[[Category:Sulfide minerals]]
[[Category:Molybdenum minerals]]
[[Category:Lubricants]]
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