FeS2, or pyrite, PbS, or galenite, ZnS, or sphalerite, CuFeS2, or chalcopyrite, etc.
"An Introduction to Chemical Science"
R.P. Williams
Copper is known to be taken into solution as copper sulphate at the surface, and to be redeposited as chalcocite where these sulphate solutions come in contact with chalcopyrite or pyrite below.
"The Economic Aspect of Geology"
C. K. Leith
Below this is a zone carrying copper in the form of chalcopyrite, enriched by chalcocite deposition from above, ranging in thickness up to 400 feet.
"The Economic Aspect of Geology"
C. K. Leith