[Rockhounds] BASIC geo-chem question...

[Dennis Buffenmyer]

I live in an area where the rock units are largely sedimentary and 
specifically, for the most part, limestone. Within the limestone there 
is  not a LOT of variety of minerals, but often we find Fluorite. I 
understand that minerals can precipitate and form in the ooze of the 
sediment by concentration, chemical reactions, salinity, and ph. What I 
am curious about is, was the fluorite always present in diluted amounts 
in the limestone, or where did the fluorine originate? Was it present as 
HF and reacted with the Ca of the limestone?? Just curious if anyone has 
any knowledge of this. NOT looking for an absolute, but perhaps a 
predominance of occurrence??