This is the oldest department at the Natural History Museum, having been established in 1901. The geological collections and displays are ranked among the best in Africa. They consist of approximately 12000 specimens comprising or rock and mineral specimens, and petrological samples. Some of the minerals are considered to be the finest of their kind in the world, for example kermesite specimen and wide variety of rare lead or zinc minerals.
The palaeontological collections and displays are not very large since they consist of approximately 2000 specimens of plants and vertebrates. Various Karoo flora and fauna are present from the Madumabisa Mudstone Formation including glossoptris, basal therapsids which are an important lineage to mammals. The Forest Sandstone yielded two types of dinosaurs Syntarsus rhodesiensis and Vulcanodon karibaensis and also the dinasaurs Euskelosaurus and Massospondylus (which is the most common dinasaur in Southern Africa), and all of which are of prime importance in the understanding of the early evolution of archosaurs and birds. Other archosaur maerial present from the Pebbly Arkose and the Jurassic – Cretaceous sediments and it includesrhycosaurs, sauropods and dinosaur footprints. Vertebrate remains from the Quaternary sediments are also present.