During a caving expedition in Namibia in February 1990, the author and Eugene Marais of the State Museum in Windhoek, visited Arnhem Cave in order to collect minerals and to study the geology. Arnhem Cave is the longest in Namibia and is situated approximately 150 km to the east of Windhoek. One sample yielded an unidentified mineral which had a X-ray diffraction pattern and a chemical composition identical to a substance synthesised by Frazier et al. (1964). Therefore it was a new species as it had not been reported in nature. The mineral has been approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association.