Recent advances in the following fields of diamond research are reviewed: morphology, growth history, characterization and classification, surface features, substitutional and non-substitutional molecular impurities, colour, age and genesis. Diamond characteristics from southern Africa, Western Australia and North America are compared in detail; >40 pristine surface features are recognized on common diamond morphologies and distinctions are made between diamonds from different kimberlite and alluvial sources, particularly in southern Africa. Only impurities of atomic size are considered. The substitutional impurities boron and nitrogen are important because of their influence on colour and diamond type. The delta 13C variations range between +5.0 and -34.4per mille and the results discussed in terms of paragenetic associations and some preliminary nitrogen isotope studies; 55 non-substitutional impurities are known, but emphasis is placed on noble gas and alkali elements because of their potentially important role in determining the age of diamond. Radiogenic impurities from within diamond currently give ambiguous diamond ages. A new age-dating method, using the impurity of nitrogen, may help resolve some of these problems. -J.M.H.
|Number of pages||24|
|Publication status||Published - 1987|