Phosphorite or mineral phosphate is made by grinding
rock phosphate, a natural mineral found in the form of
sedimentary rocks containing various calcium phosphates.
It is used as a phosphatic fertilizer, and is a primary
source of phosphorus. It is a mineral containing calcium
phosphate with hydroxyl groups or is hydroxy apatite.
Phosphorite is a continental phosphatic rock,
consisting of concretions of collophanite, found in
decalcification clays. The most famous phosphorites are
from Causses du Quercy (France).