The Collaborative International Dictionary
Francolite
Francolite \Fran"co*lite\, n. (Min.) A variety of apatite from Wheal Franco in Devonshire.
Wiktionary
francolite
n. (context mineral English) A variety of apatite.
Wikipedia
Francolite
Francolite is a carbonate rich variety of the mineral fluorapatite and is present in most sedimentary phosphorites. It has a variable chemical composition which can be represented by (Ca,Mg,Sr,Na)(PO,SO,CO)F. The mineral was named after its occurrence at Wheal Franco, Whitchurch, Tavistock District, Devon, England.