Sixteen samples of Middle and Upper Chalk from the Chilterns yielded what appear to be fragments of fish scales, spines, and bones, which consist of collophane. X-ray examination by the powder method shows that the material has an apatite-type structure with cell dimensions close to those previously reported for francolite. Examination of single grains shows that the optical anisotropy is due to preferred orientation of the c-axes of the crystallites and this direction corresponds to the faster vibration direction. Such grains are found to be pseudouniaxial negative. Preferred orientation could not be detected in isotropic grains.

A singly terminated transparent, deep-garnet-red crystal originally weighing 1·7g. from a gem gravel from Mogok, Burma, proves to be a new mineral having Al2O3 76·2, SiO2 5·6, B2O3 2·2, CaO 15·7, H2O 0·7, Fe2O3 and MnO traces, total 100·4. Sp. gr. 4·01; ω 1·8159, ɛ 1·7875; H 8. The hexagonal unit cell has a 8·725, c 8·46 Å., space group P63, P63/m or P63 22, and contains approximately 38 O. The name painite is proposed in honour of A. C. D. Pain who recognized the unusual nature of the crystal.