3Ca3(PO4)2-CaF2;a naturally occurring fluorophosphate of calcium.
Results from our forum
... significant and related to cooling through very low temperatures. This idea was supported by helium diffusion measurements on gem quality Durango fluorapatite which indicated a closure temperature of just 100 ? +/- 3O”C, a value recently confirmed on several additional apatites (Lippolt et al., ...
See entire post