The name chalcocite comes from its composition (the Greek word chalkos means copper). Chalcocite is a very important copper ore. Good crystals are not often found, more often chalcocite is found as large masses. Chalcocite is sometimes found as a primary mineral, but more often is the result of oxidation of other copper sulfides yielding the enriched copper ore chalcocite.
| Cu2S |
|
| Sulfide |
|
| Monoclinic |
|
| 2/m |
|
| 2.5-3 |
|
| 5.5-5.8 |
|
| {110} poor |
|
| conchoidal |
|
| Gray, black when tarnished |
|
| Dark gray |
|
| Metallic |
|
| Opaque |
|
| Notable Localities: |
Cornwall, England; Bristol, Connecticut |
| Uses: |
Ore of copper |
Specimens:
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