Rutile is titanium oxide, TiO2 It is a common accessory mineral in high-temperature and high-pressure metamorphic rocks and in igneous rocks. There is a wide colour variation, with the golden variety most sought after for decorative purposes. The crystal form is usually slender and acicular. The crystals in this specimen are not very well defined, are short and stubby, and almost black. It was collected from Mount Crawford, South Australia.