Francolite is a carbonate rich variety of the mineral fluorapatite[1] and is present in most sedimentary phosphorites.

It has a variable chemical composition which can be represented by (Ca,Mg,Sr,Na)10(PO4,SO4,CO3)6F2−3.

[2] The mineral was named after its occurrence at Wheal Franco, Whitchurch, Tavistock District, Devon, England.

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