|1959 International Geophysical Year (2nd issue)|
|1884: "Strategic Metals"|
The stamp designer Hein Botha has produced other geology stamps for Namibia and also the succulent plants definitive series for South Africa whose curious shapes have a rock shaped element to them.
And to complete the set here are the wonderfully named Cinnabar and Wolframite.
An entry to Viridian Postcard's Sunday Stamps theme of - Geology and the Earth