Online Encyclopedia

Make a correction

Your email address will not appear on the site. Note, comments may take some time to be approved.

Back to article: MELACONITE

Your email: Article name: Article content:

MELACONITE, a mineral consisting of cupric oxide, CuO, and known also as black copper ore. In appearance it is strikingly different from cuprite (q.v.) or red copper ore, which is cuprous oxide. Crystals are rare; they belong to the mono-clinic, or possibly to the anorthic system, and have the form of thin triangular or hexagonal scales with a steel-grey colour and brilliant metallic lustre. More often the mineral is massive, earthy or pulverulent, and has a dull iron-black colour. Hence the name melaconite, from the Greek µEras, black and rthvis, dust, which was originally given by F. S. Beudant in 1832 in the form melaconise. The crystallized Vesuvian mineral was later named tenorite, a name commonly adopted for the species. The hardness of the crystals is 3-4, but the earthy and powdery forms readily soil the fingers; the spec. gray. is 5.9. Crystals have been found only at Mt Vesuvius, where they encrust lava, and in Cornwall. The other forms of the mineral, however, are common in copper mines, and have resulted by the alteration`' of chalcocite, chalcopyrite and other copper ores, on which they often form a superficial coating.	(L. J. S.)