A
typical piece of Chalcopyrite showing a weathered surface that has produced an iridescence.
The top left corner has been broken to show the bright metallic luster of a
fresh surface.
Small tetrahedral crystals of
Chalcopyrite in a parallel growth over a Sphalerite crystal. Note that
many of the Chalcopyrite crystal faces are reflecting the light towards the
camera indicating that they are in a parallel alignment.
CHEMISTRY CuFeS2 Copper iron sulfide
CRYSTALLOGRAPHY Tetragonal
CRYSTAL GROWTH AND HABITS Tetrahedral crystals are common, often with scalenohedral faces. Chalcopyrite is commonly found as massive as, well as compact and occasionally as reniform masses.
COLOR AND OTHER OPTICAL PROPERTIES Chalcopyrite is normally brass yellow but often it is tarnished to dark brown. The tarnish can produce a colorful iridescence and as a result it is often called "peacock ore". Chalcopyrite is opaque.
HARDNESS 3.5 - 4
SPECIFIC GRAVITY 4.1 - 4.3
LUSTER Golden metallic
STREAK Greenish black to black
BREAKABILITY Uneven with one very poor cleavage direction
OCCURRENCE A primary sulfide formed in hydrothermal veins
ASSOCIATED MINERALS Pyrite, Sphalerite, Galena, other copper sulfides