Covelien "eyes" pendant from Peru.

The mineral covelte or coveline is a copper-sulfide having the chemical formula CuS. Also, it may contain some iron. The opaque indigo blue or darker mineral has a hexagonal crystal system, with the ribs a = 379.2 pm and c = 1634 pm (space group P63 / mmc). The crystals are plate-shaped, due to perfect cleavage along the crystal plane [0001]. The color is blue. The color line is lead gray, shiny. The structure of covellien is quite complicated. A third of copper and sulfur atoms form a flat layer with a graphite structure (or more precisely boron nitride). Two-third forms of the sulfur atoms of sulfur pairs S2, as is also known from the pyrite-structure which are perpendicular to the planar layer therebetween with copper atoms. Coveline is a metallic conductor. Electronic can best be described as Cu + 3S-S22- Do with a delocalized hole in the valence band which is mainly sulfur character. The mineral is named after the Italian mineralogist Nicollo Covelli (1790-1829). Covelite consists of approximately 66.5% copper, making it, as it is found in large quantities, is a very costly copper ore. The remaining 33.5% consists mostly of sulfur.