Acuminite is a rare halide mineral with chemical formula: SrAlF<sub>4</sub>(OH)÷(H<sub>2</sub>O). Its name comes from the Latin word acumen, meaning "spear point". Its Mohs scale rating is 3.5.
Acuminite has only been described from its type locality of the cryolite deposit in Ivigtut, Greenland.