Creedite - Encyclopedia
Class : Sulfates, chromates, molybdates
Subclass : Hydrated sulfates
Crystal system : Monoclinic
Chemistry : CaAl2(SO4)(F,OH)10 2H2O
Rarity : Rare
Creedite is a rare fluorinated, hydrated sulphate. It takes its name from its discovery location : the Wagon Wheel Gap vein in the Creede deposit (Colorado, USA). It is found in small, short acicular to prismatic crystals, frequently grouped in radiated aggregates or geodic masses, colorless, yellow, orange or white, rarely purple. The frequency of creedite in fluorite and barite veins suggests an hydrothermal origin for this mineral.
Main photo : Creedite de Navidad Mine, Durango, Mexico
Creedite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
Some specimens from Qinglong Mine (China) were dyed purple with ink to facilitate sale. The deception is easily identifiable, the dye being soluble in acetone and concentrating in the cracks of the treated specimens...
Hardness : 4
Density : 2.71 to 2.73
Fracture : Conchoidal
Streak : White
TP : Transparent
RI : 1.461 to 1.485
Birefringence : 0.024
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None
Solubility : Acids
Magnetism : None
Radioactivity : None