South Africa's economy is a mixture of Third World and First World. On the one hand there is a subsistence agricultural economy (barely changed since the 19th century); and on the other there is a modern, industrailised economy.
Mineral wealth has been the key to South Africa's development, as until diamonds were discovered at Kimberley in 1869 and gold on the Witwatersrand in 1886, the national economy was completely agricultural.
Today, mining remains important to the national economy, and South Africa is the world's leading supplier of diamonds, platinum, gold, chromium, manganese and vanadium.