MOLYBDENITE
Molybdenite is a molybdenum sulfide mineral (MoS2).
It has hexagonal crystals, metallic luster, a bright silvery color, and a dark
gray streak. It is fairly soft (H=2) and has one cleavage.
Molybdenite is especially distinctive in being flexible - thin scales or plates
of the stuff will easily bend but won't snap back into shape like biotite or
muscovite mica.
Molybdenite is nearly identical to graphite (C)
in its physical characteristics. Graphite is a principally a metamorphic
mineral. Molybdenite is usually an igneous mineral, occurring in
hydrothermal veins and pegmatites. It also occurs in some contact
metamorphic rocks (skarns).
Molybdenite in quartz-rich pegmatite (above & below; above: 5.1 cm tall;
below: 4.1 cm across) from the Moly Hill Mine, near Malartic, Preissac
Township, southwestern Quebec, Canada.
The pegmatite intrudes the Preissac-Lacorne Batholith
(Abitibi Greenstone Belt, late Neoarchean, 2.630-2.675 billion years).
Dark silvery-gray = molybdenite; glassy whitish-gray =
quartz; shiny brownish-gray in sample shown below = muscovite mica.
