In covellite some of the copper ions are at the center of sulfur tetrahedrons that are linked on their bases to form sheets. The other copper ions are combined with three sulfur ions in flat triangular groups similar to the triangular groups of the typical carbonates These triangular groups lie in a plane between the tetragonal sheets. The perfect cleavage of covellite into sheets is easily explained by this structure. Luster is metallic Transparency crystals are opaque to translucent in very thin cleavage sheets. Also massive and in small grains in sulfide ore bodies.
Cleavage is perfect in one direction forming thin sheets.
Fracture is flaky. Hardness is 1.5 - 2. Specific Gravity is 4.6 to 4.8 Streak gray to black. Associated Minerals include pyrite , chalcocite , chalcopyrite , cuprite , bornite and other copper sulfides . Best Field Indicators are crystal habit, cleavage, density, iridescence and color.