Mantle-carbonatite conception of diamond genesis is developed. Generalized composition diagram of multi-component heterogeneous parental medium for diamond and primary inclusions is first constructed. Boundary compositions of the diagram are represented by components of peridotitic and eclogitic parageneses, mantle carbonatites and C-O-H-fluids, accessory phases both soluble in the carbonate-silicate melts and insoluble in them and carbon. Phase relations at 7 GPa of the multi-component system eclogite-carbonatite-sulfide-diamond are studied. A "syngenesis diagram" for diamond, paragenetic and xenogenetic minerals (including diamond solubility curves in carbonate-silicate and sulfide melts) is constructed. Physicochemical mechanism of formation of natural diamond and paragenetic minerals is revealed. A genetic classification of primary inclusions in natural diamonds is worked out.
Key words: diamond genesis, parental medium, experiment, syngenesis diagram, classification of inclusions