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Chalcocite, copper(I) sulfide (Cu2S), is an important copper mineral ore. It is opaque, being colored dark-gray to black with a metallic luster. It has a hardness of 2Â½ - 3. It is a sulfide with an orthorhombic crystal system. Chalcocite is sometimes found as a primary vein mineral in hydrothermal veins. However, most chalcocite occurs in the supergene enriched environment below the...
- Sleep; the state or condition of being asleep.
- The state or condition of numbness of a part due to pressure on a nerve: as, the obdormition of a limb.