Zirkelite is an oxide mineral with the chemical formula . It occurs as well-formed fine sized isometric crystals. It is a black, brown or yellow mineral with a hardness of 5.5 and a specific gravity of 4.7. Name and discovery Zirkelite was first discovered in Brazil in 1895. It was named for German petrographer Ferdinand Zirkel (1838–1912). Occurrence Initial discovery was from the Jacupiranga carbonatite, Sao Paulo, Brazil. It is also found in Canada, Kazakhstan, Norway, Russia, South Africa, the United Kingdom, and the United States. See also List of minerals named after people References Webmineral data Mindat localities Mineral Data Publishing Calcium minerals Thorium minerals Zirconium minerals Titanium minerals Niobium minerals Lanthanide minerals Cubic minerals Minerals in space group 225 Oxide minerals Minerals described in 1895