ELECTROSTATIC TECHNIQUE FOR REVEALING INTERNAL STRUCTURE IN DIAMONDS

Using a simple technique based on electrostatic charging (essentially xerography of crystals), it has been found possible to reveal internal structure which appears to be directly related to that seen by other methods. It is necessary to expose the interior of the crystal in order to see the internal growth structure - i.e. to intersect the external growth surfaces since the latter are essentially homogeneous with respect to the electrostatic technique. If there are heterogeneities or discontinuities in the growth history of a crystal, we have found that the table, crown and pavilion facets of a cut stone are adequate intersecting planes for revealing patterns by the electrostatic technique. This technique might be the basis for a simple fingerprinting method for some gemstones. © 1979 Chapman and Hall Ltd.