1. Gold (Au): South Africa is the world's largest producer of gold.
2. Platinum (Pt): South Africa is also the world's largest producer of platinum.
3. Chromium (Cr): South Africa is a major producer of chromium, which is used in stainless steel and other alloys.
4. Manganese (Mn): South Africa is a significant producer of manganese, an important component in steel production.
These four elements are all transition metals, meaning they have partially filled d-orbitals in their atoms, which gives them unique properties and makes them valuable in various applications.