Specimens of molybdenite in a feldspar matrix from Buskerud in Southern Norway. Molybdenum disulfide (MoS2) otherwise known as Molybdenite is the primary ore of the rare earth metal Molybdenum. This element rarely occurs in pure form in nature and it is from minerals like molybdenite that it can be extracted. The mineral is often formed in hydrothermal veins. In recent years it has become an important factor of alloy production, particularly that of steel and stainless steel. The mineral is similar to Graphite, both in lustre and habit - molybdenite also leaves behind residue when touched (although this is harmless). This interesting property is a result of the molecular structure of the mineral, in which one molybdenum atom is sandwiched between two sulphur atoms, which is repeated in layers, allowing the individual layers to move over each other in the same way a conveyor would. Samples are supplied in a white card tray with an information label. A must have addition to any mineral collection.