Photos of gold ores, quartz, telluride gold ore and gold ...
This is a piece of gold ore from the famous Witwatersrand gold deposits of South Africa. The ore consists of conglomerate pebbles mostly of quartz, in a sandy matrix, with abundant pyrite in the cement. The gold, which occurs in the cement but not in the pebbles, is closely connected with the pyrite and is not visible to the naked eye.