Laurite
Laurite is an opaque black, metallic ruthenium sulfide mineral with formula: RuS2. It crystallizes in the isometric system. It is in the pyrite structural group. Though rare, it occurs in many parts of the world.
Laurite has a Mohs hardness of 7.5 and a specific gravity of 6.43. It can contain osmium, rhodium, iridium, and iron substituting for the ruthenium.