Knowing the age of diamonds is critical to understanding their formation and likely distribution in the mantle. Re-Os isotope analyses of synergetic sulphide inclusions allows dating of individual diamonds by isochron and model age methods. This method will be applied to a suite of well-characterised Siberian diamond inclusions from several different kimberlite pipes. We will aim to determine the ages of eclogite-suite and periodite-suite diamonds, which may provide clues as to their different modes of origin. Shrimp ii Pb-Pb isotope and S-isotopic measurements will further constrain the age and origin of the sulphides and hence the diamonds. N-aggregation studies on the host diamonds will independently assess mantle residence times. We will examine absolute age differences between cores and rims of diamonds by laser cutting fragments of diamonds with multiple inclusions.