THE APPLICATION OF INAA TO THE GEOCHEMICAL ANALYSIS OF SINGLE DIAMONDS

Instrumental neutron activation analysis (INAA) has been applied to th e analysis of 62 small (0.01-0.5 carat), single, inclusion-bearing and inclusion-free diamonds from South Africa, Brazil and Colorado. Up to 40 elements were detected at the ppb and ppt levels in individual dia monds of the eclogitic (basaltic affinity) and the peridotitic (ultram afic) paragenesis. The data obtained in this study can be used to dist inguish between diamonds from the eclogitic and peridotitic paragenese s and provides geochemical information on the environment in which dia monds crystallize. Further, the technique may prove to be useful in '' fingerprinting'' diamonds of different provenance areas.