Precambrian diamond crystals from the Siberian craton

Abstract

Analysis of diamond grains from placers in the northeastern Siberian craton shows that some diamond varieties (round dodecahedra, varieties II and V-VII in the classification of Orlov) may originate from Precambrian sources. The Precambrian diamonds have different sedimentation histories. Namely, diamonds of varieties V-VII are most strongly rounded though being the most resistant to wear. Therefore, they should have the longest history of dispersal and transport, and thus should be derived from the oldest primary deposits.