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Copper and mispickel are mined only in small quantities.

It is a mineral of secondary origin, having resulted by the decomposition of copper ores and mispickel in the upper part of mineral veins.

One gram of copper pyrites, blende, fahlerz, or mispickel, yields 7 or 8 grams of lead, whilst 1 gram of antimonite will give 6, and 1 gram of galena only a little over 3 grams.

The gold is also often visible to the naked eye in all the associated minerals, and particularly in the mispickel and blende.

With mispickel, and those substances which easily give off arsenic on heating, the substance is first treated with nitric acid, evaporated to dryness, and then the residue is treated in the way just described.