Nanoscale mineral inclusions in the diamond phase of carbonados

Investigations show that the Brazilian carbonados represent the microscale polycrystalline aggregates of the diamond phase with xenomineral (nondiamond) material in interstices and pores. More than 100 mineral species and varieties, which represent almost all major types and classes of the modern mineralogical nomenclature, have been recognized among such impurities so far. In terms of origin, they can be subdivided into three groups: (1) proto- and syngenetic impurities; presumably endogenic-epigenetic impurities; and (3) probably exogenic-epigenetic impurities. The first group includes two specic varieties:(i) unusual solid solutions with the composition and phase homogeneity suggesting the mantle origin of carbonado and (ii) primary gasuid inclusions with an anomalous concentration of carbon monoxide.