The geology of Rwanda comprises Mesoproterozoic metasediments, largely quartzites, sandstones, and shales of the Burundian Supergroup which are locally intruded by granite.
In eastern Rwanda are the “older granites” along with granitic-gneisses and migmatites of Palaeoproterozoic age.
In the northwest and southwest are Neogene volcanics, ranging in age from Cenozoic to recent.
[1]: 190 A significant portion of Rwanda's economy is based on mineral extraction.
Rwanda is Africa's second highest producer of tin and coltan, accounting for 20% and 30% of the country's output, respectively.