Editing Molybdenite (section)

==Description==
===Occurrence===
[[File:Molybdenit 1.jpg|thumb|A less pure sample of molybdenite mineral]]
Molybdenite occurs in high temperature [[hydrothermal]] [[ore]] deposits.
Its associated minerals include [[pyrite]], [[chalcopyrite]], [[quartz]], [[anhydrite]], [[fluorite]], and [[scheelite]].  Important deposits include the disseminated porphyry molybdenum deposits at [[Questa, New Mexico]] and the [[Henderson molybdenum mine|Henderson]] and [[Climax mine|Climax]] mines in [[Colorado]]. Molybdenite also occurs in [[porphyry copper]] deposits of [[Arizona]], [[Utah]], and [[Mexico]].

[[File:Molybdenite Under normal and polarized light.jpg|thumb|Molybdenite under normal and polarized light]]
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.

===Features===
[[File:Molybdenite.GIF|thumb|right|Crystal structure of molybdenite]]
Molybdenite is extremely soft with a metallic luster, and is superficially almost identical to graphite, to the point where it is not possible to positively distinguish between the two minerals without scientific equipment. It marks paper in much the same way as graphite. Its distinguishing feature from graphite is its higher specific gravity, as well as its tendency to occur in a [[Matrix (geology)|matrix]].