Note on Peculiar Quartz-Pseudomorphs Found at the Owera Mine, Opitonui, North Island, New Zealand

Extract

The Owera Mine is opened on a line of lode or reef consisting of small auriferous quartz veins traversing decomposed hyperstheneaugite andesite. The quartz of the veins is highly ferruginous, and full of little patches of brown hæmatite indicating decomposed pre-existing pyrite, remnants of which are occasionally observed. It is in connection with the veins in the soft country rock and near the surface that the pseudomorphs under notice are found, and it seems probable that they owe their origin to infiltration of silica into cavities left by removal of calcite, though none has the actual form of a crystal of that mineral, which, in fact, is quite absent at the place Yet the specimen (No. 2) found with some of the pseudo-crystals tends to support this supposed origin, the hollows and, more clearly, wax impressions of them showing that the removed crystals were scalenohedra.