The rocks are probably of quartz, i.e.
Gold is obtained chiefly from quartz reefs, but there are still some important alluvial deposits being worked.
The greatest development of quartz reefing is found in Victoria, some of the mines being of great depth.
The conglomerates consist almost entirely of pebbles of quartz set in a hard 2 At the Standerton gauge on the Vaal in 1905-1906, a year of extreme drought, the total flow was 8,017,000,000 cub.
from quartz mines.