Diamonds from the Nassau Mountains, Suriname

Alluvial diamonds have been found in Suriname since the late 19th century, but to date the details of their origin remain unclear. Here we describe diamonds from Paramaka Creek (Nassau Mountains area) in the Marowijne greenstone belt, Guiana Shield, north-eastern Suriname. Thirteen samples were studied, consisting mainly of euhedral crystals with dominant octahedral and dodecahedral habits. They had colourless to brown to slightly greenish body colours, and some showed green or (less commonly) brown irradiation spots. Surface features showed evidence of late-stage resorption that occurred during their transport to the earth's surface. The studied diamonds were predominantly type IaAB, with nitrogen as both A and B aggregates. In the DiamondView most samples displayed blue and/or green luminescence and concentric growth patterns. Their mineral inclusion assemblages (forsterite and enstatite) indicate a peridotitic (possibly harzburgitic) paragenesis.