Malachite on Chalcopyrite

Sample of brass-yellow tetrahedral subhedral Chalcopyrite with emerald-green Malachite encrusting on the Chalcopyrite crystals. Average Chalcopyrite crystal size: 1.5 cm x 1.0 cm x 1.6 cm. Malachite (Cu2CO3(OH)2) can be emerald-green, grass-green or dark green in colour. Lustre is adamantine, silky or dull and streak is light green. Hardness is 3 1/2 to 4 and cleavage is perfect in one direction crosswise. Malachite usually occurs as radial, fibrous, botryoidal, stalactitic, incrusting, earthy or long and short prismatic crystals (rare). Chalcopyrite (CuFeS2) can be brass-yellow or golden-yellow and is often tarnished iridescent or deep blue, purple and black. Lustre is metallic and streak is greenish black. Hardness is 3 1/2 to 4 and cleavage is poor in one direction. Chalcopyrite usually occurs as tetrahedral crystals with uneven faces with striations but can also be massive, compact, granular or disseminated.