gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1972.038.299.11 Natural and Laboratory α-Particle Irradiation of Diamond Vance E. R. 1 Milledge H. J. Chemistry Department, University College, London

Present address: Dept. of Solid State Physics, Australian National University, Canberra, A.C.T. 2600, Australia.

 9 1972 38 299 878 881 15 9 1971 Copyright © 1972, The Mineralogical Society 1972 Summary

To produce a lattice expansion readily detectable by conventional X-ray photographic means in α-irradiated diamond, a dose of order 1018 α.cm−2 is required. Such a dose could be produced by pitchblende in ∼2 × 108 yr. and a previously reported lattice expansion in a natural diamond could therefore have occurred by long-term contact with a radioactive material. α-particle doses greater than ∼1014 cm−2 produce observable green colouration on the surface of an initially colour-less diamond.