Description
The mineral creedite is named after the place where it was first found, the Creed Quadrangle in Colorado. Creedite is a hydrated calcium-aluminum sulfate fluoride with the chemical formula Ca3Al2(SO4)F7.5(OH)2.5·2(H2O). It belongs to the halide group. The transparent to translucent white, orange, or purple mineral has a vitreous to oily luster, a white streak color, and perfect cleavage according to [100]. The crystal system is monoclinic. Creedite has an average density of 2.71, a hardness of 3.5, and is not radioactive. The birefringence of creedite is 0.0240. The type locality of creedite is Wagon Wheel Gap, Creed Quadrangle, Colorado, United States. The mineral is also found in Durango and Santa Eulalia, Mexico.
