What is Molybdenite?
Molybdenite combines the tactile softness of graphite with the visual weight of a metallic ore. Its thin flexible plates are a direct expression of weak bonding between sulfide layers and a signature of porphyry systems.
Mineralogy and crystal structure
Reference formula: MoS2. Molybdenite is a layered hexagonal molybdenum disulfide. Its perfect basal cleavage and greasy feel are characteristic, and its 2H polytype is the common natural structural model; 3R stacking can also occur. Molybdenite is classified with sulfides and has a hexagonal crystal system. Typical hardness is 1–1.5 on the Mohs scale and specific gravity is approximately 4.7–4.8.
Colour, lustre and habit
Typical colours include lead-grey, silver-grey, black. The usual platy, hexagonal, foliated habit and metallic, sub-metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Molybdenite forms in or is associated with porphyry copper-molybdenum systems, greisens, quartz veins and high-temperature hydrothermal deposits. Important documented localities include the United States, Canada, Chile, Peru, China, Norway and Russia.
A graphite-like metal with economic importance
Molybdenite combines the tactile softness of graphite with the visual weight of a metallic ore. Its thin flexible plates are a direct expression of weak bonding between sulfide layers and a signature of porphyry systems.
Collecting and care
Extremely soft and cleavable: keep separate from harder specimens and do not rub the metallic plates.
