Phosphorite
A phosphorite or phosphate rock is a non-detrital sedimentary rock which contains high amounts of phosphate bearing minerals.
Phosphorite Media
Peloidal phosphorite, Phosphoria Formation, Simplot Mine, Idaho. 4.6 cm wide.
Fossiliferous peloidal phosphorite, (4.7 cm across), Yunnan Province, China.
Guano phosphorite mining in the Chincha Islands of Peru, c. 1860