Teufelskuppe is an approximately circular group of hills 1 km in diameter and rising to 120 m. Carbonatite appears to form a complex of cone sheets dipping inwards at 5-25° which intrude biotite schist and amphibolite. A conical hill to the north, which has a band of black ferruginous ooliths, which might be accretionary lapilli (Verwoerd, 1093), at its base, is probably a volcanic neck. Alvikite is predominant amongst the cone sheets but dolomite carbonatite is also represented. Some specimens contain euhedral magnetite and apatite crystals that stand out on weathered surfaces while others have a streaky flow-banding, a porphyritic texture with dolomite phenocrysts, or abundant fragments of country rock. High Sr values have been reported (Verwoerd, 1993).