[5] A black colloidal precipitate of CuS is formed when hydrogen sulfide, H2S, is bubbled through solutions of Cu(II) salts.

There is also an amorphous high pressure form[9] which on the basis of the Raman spectrum has been described as having a distorted covellite structure.

[10] The crystal structure of covellite has been reported several times,[11][12][13] and whilst these studies are in general agreement on assigning the space group P63/mmc there are small discrepancies in bond lengths and angles between them.

The covellite unit cell contains 6 formula units (12 atoms) in which: The formulation of copper sulfide as CuIIS (i.e. containing no sulfur-sulfur bond) is clearly incompatible with the crystal structure, and also at variance with the observed diamagnetism[15] as a Cu(II) compound would have a d9 configuration and be expected to be paramagnetic.

This contradicts a formulation based on the crystal structure and obeying the octet rule that is found in many textbooks (e.g.[6][20]) describing CuS as containing both CuI and CuII i.e. (Cu+)2Cu2+(S2)2−S2−.