This is the cluster of greenish-yellow francolite crystals. Dimensions: 2.8 x 2.6 x 1.6″ (7.2 x 6.7 x 4.1cm). Weight – 8oz (226 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.