This is the raw greenish-yellow francolite specimen. Dimensions: 2.4 x 1.6 x 0.4″ (6 x 4 x 1cm). Weight — 1.3oz (38 grams). Origin: Russia, Yakutia.
Some information about 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)10(PO4,SO4,CO3)6F2-3. The mineral was named after its occurrence at Wheal Franco, Whitchurch, Tavistock District, Devon, England.