It is very difficult to separate iron pyrites, copper pyrites, mispickel, or sulphate of barium, from silver ores.
Both iron and copper pyrites contain sulphur and the Marquis with his usual enthusiasm decided to build a sulphuric acid plant at the site.
Yet on his recovery, Gunnar realises that they are valuable copper pyrites, in sufficient quantity to restore the house's fortunes.
The Pioneer Company's lode, at Collingwood, seems to belong to this class, showing a grey sulphide, and copper pyrites, in a quartz matrix, which has been tested with favourable results.
Strings of copper pyrites lay along the junction of the dyke with the conglomerate, and to a minor extent at its junction with the slate.