Soft Metallic Mineral represents a molybdenum disulfide (MoS2) mineral that has the same feel and appearance of graphite. The layered structure of this mineral gives it the effect of a lubricant. Atomic structure wise, the molybdenite mineral atoms forms a sheet between two layers of atoms of sulfur. Even though the bonds of the Molybdenum and Sulfur appear strong, the sulfur atoms forming the upper and lower layers do not have a good interaction, leading to weakness that creates slippage and cleavage planes. Molybdenum uses the hexagonal system of crystals to crystallize into the polytype (2H) and it uses the trigonal structure to form polytype 3R.
Derivation of Name
From the Greek word molubdos (lead)
Occurrence and Source
Molybdenite is found in hydrothermal ore deposits at high temperatures. Its related minerals are: Pyrite, Chalcopyrite, Fluorite, Quartz, Anhydrite and Scheelite. Significant deposits include the Henderson and Climax mines in Colorado and deposits at Questa, in New Mexico. It’s also found in copper deposits in Mexico, Utah and Arizona.
The rhenium element’s presence is a regular feature as an alternate for molybdenum, generally in the ppm range, but with a normal count of 1–2%. Sometimes you can perceive a High content of rhenium leading to a structural variety that only diffraction X-ray technics can show. Rhenium comes only from this mineral.
Not used as a gemstone.
The mineral is especially soft and one can easily confuse it with graphite. Graphite is characterized by a brow gray to a black, gray streak in its silver metallic color. On the other hand the metallic mineral has a streak of bluish – silver. Because of too slight a difference, it is suggested to see the color of the two streaks adjacent to one another to understand the difference between the 2 minerals. When you see larger samples sans the host rock, molybdenite’s higher specific gravity is a source of differentiation.
It has a silver metallic color with a bluish cast.
1.5 - 2.0