Cuprite
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- Lustre:Adamantine, Sub-Metallic, Earthy
- Transparency:Transparent, Translucent
- Colour:Dark red to cochineal red, sometimes almost black.
- Streak:Shining metallic brownish-red.
- Hardness:3½ - 4 on Mohs scale
- Tenacity:Brittle
- Cleavage:Imperfect/Fair Interrupted on {111}, more rarely on {001}.
- Fracture:Conchoidal
Cuprite is a red, semitransparent oxide of copper. Quite difficult to find well crystallised material, and not found on all old copper mines, it is fairly easy to spot as the red glints stand out among the greens and blues of the other secondary copper minerals. Its earthy form is more common, known as 'tile ore'. This variety makes the earth in some old copper mines a distinctly red colour in areas where it is abundant.
As a semiconductor, the earthy form seems not useful or conductive at all. In it's well crystallised form it is extremely good, very eager and easy to find semiconducting junctions. The test here was done on a single crystal with one silver contact to provide the ohmic connection, and one steel to provide the point contact. Cuprite is the subject of ongoing semiconductor research, for use in solar panels.
Part of the Arts Council England R&D project is to research new mine sites to try and locate more specimens of this mineral to use.
