Silical Oxide of Zinc

Tab. 156 shows the pretty yellow variety of this substance in neat crystals: the present is colourless, and shows some variety in the crystals which are attached to the sides of hollows in massive Fluor. The front figure is of a remarkably pretty specimen, having a largish bundle of thickish crystals in the front, and deeper in the hollow, several fine crystals in very thin plates, modified as at the right hand figure. The crystals in the bundle are as in the middle figures. I add another figure of a specimen found on the same mass of Fluor, with the crystals like the left hand figure.

This is part of the same gangue that belonged to the last rarity, and in common with it partakes of the same substances; dispersed through part of it, however, there are many minute rubes of Sulphuret of Lead. The hollows are lined with transparent White Fluor, some of which is delicately coated with Yellow Oxide of Iron, and speckled with decomposing pyrites. Some Carbonate of Lime in modified metastatic crystals also accompany it: they are remarkably fine on the back of the large specimen.

Mr. Smithson has made some observations on this species, as mentioned in our tab. 156.