The Picture Battle!!! in Grand Theory of Everything Posted February 14, 2007 usedHONDA said "Apatite Ca5(PO4)3(OH,F,Cl)" You should have decided between Ca5(PO4)3(OH), Ca5(PO4)3F and Ca5(PO4)3Cl. You can't say three things at once by using a general formula. Maybe it woulb be good to add a link to wikipedia or something if you use such uncommon things. I still have no idea in which way Apatite could "beat" hydrochloric acid. But, anyway, hot Apatite Ca5(PO4)3(OH) > Apatite because then it becomes phosphorescating.