Description:
Molybdenite is a very soft metallic mineral. It can
be easily confused with graphite, but not with many
other minerals. Graphite has a darker black-silver color
and a black-gray to brown-gray streak, whereas molybdenite
has a bluish-silver color and streak. Unfortunately,
the difference is so slight that it is recommended that
the two minerals be seen side by side. Their respective
streaks should also be observed side by side to appreciate
the differences. If larger samples, free of host rock,
are available, then the greater density of molybdenite
can be used for identification.
Molybdenite's structure is composed of molybdenum ions
sandwiched between layers of sulfur ions. The sulfur's
layers are strongly bonded to the molybdenum, but are
not strongly bonded to other sulfur layers, hence the
softness and perfect cleavage. It is soft enough to
leave a mark on paper and fingers. Its greasy feel is
due to its extreme softness. Molybdenite or "Moly
Ore" as it is sometimes called, is a very high
luster mineral and can be an interesting mineral to
add to a collection. |