Euhedral to subhedral crystals of blue apatite from 1 to 7 cm long occur in a partly serpentinized marble from a quarry near Matale, north-ccntral Ceylon.

The chemical composition of the apatite is as follows: CaO 55.24, MnO 0.02, P2O5 40.91, F 1.05, Cl 2.31, H2O 0.68, CO2 1.18, Fe2O3 0.03, 0 ≡ F, Cl 1.17, total 100.25 percent. The calculated cell contents on the basis of 26(O, OH, F, Cl) are

which corresponds to the theoretical formula Ca5(PO4)3(OH, F, Cl); the ratio F:Cl:OH is The composition, as determined, is unusual, and warrants the name carbonate-bearing fluor-chlor-hydroxyapatite. The other properties are ϵ 1.646, ω 1.651, density (at 25°C) 3.18.

The apatite crystals are thought to have been formed during regional metamorphism, under granulite facies conditions, of a phosphatic sedimentary limestone.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.