Kostovite is a rare orthorhombic-pyramidal gray white telluride mineral containing copper and gold with chemical formula AuCuTe4. It was discovered by Bulgarian mineralogist Georgi Terziev (Георги Терзиев) (1935–1972), who named it in honor of his professor Ivan Kostov (Иван Костов) (1913–2004). In 1965 kostovite was approved as a new species by the International Mineralogical Association. The type locality is the Chelopech copper ore deposit, Bulgaria. Small deposits have also been found in Kochbulak (Eastern Uzbekistan), Commoner mine (Zimbabwe), Kamchatka (Russian Far East), Ashanti (Ghana), Buckeye Gulch (Leadville, Colorado, US), Bisbee (Arizona, US), Kutemajärvi (Finland), Coranda-Hondol (Romania), Glava (Sweden), Bereznjakovskoje (Southern Urals, Russia), Moctezuma (Sonora, Mexico),