English: Cose-up view of Nebo granite in the Tswaing crater wall, Gauteng, South Africa, to which an age of just over 2 billion years is assigned.
Nebogranite consists of quartz, potassium feldspar and subordinate hornblende or biotite. The granite thickness is 3,000 m and is predominantly formed in layers, with a corresponding spectrum of properties. From bottom to top it changes from 1. a very coarse-grained, gray granite to less coarse-grained gray and red granite, with locally a red granophyric granite, 2. decrease in the amount of dark minerals, 3. replacement of hornblende by biotite as the most prominent dark mineral, 4. a decrease of Ba, Sr and Eu and an increase of Rb.