Report on the Geology & Gold Fields of Otago
Grinding and Polishing Materials
Grinding and Polishing Materials.
Good sharp sandstone, or gritstone, suitable for grindstones, is found in the Horse Range, while whetstones, and scythe stones could probably be supplied from some of the more arenaceous mica schists, as at Mount Alta. Hone slate and Lydian stone are not uncommon in the Kakanui and Kaikoura formations; and polishing power (diatomaceous earth) is found in Strath Taieri, and probably also in some of the other old lake basins.