Carbonado, a polycrystalline diamond variety, has a very controversial genesis. The geologic setting of the carbonado-bearing precambrian sequences in the Serra do Espinhaço, and other aspects regarding the genesis, seem to favor one specific hypothesis: the mycrocrystals that make up the carbonado could have been formed by the "usual" way within the mantle and were brought up to the crust together with large diamond crystals found in the same sequences; in a later stage, the mycrocrystals formed aggregates in a radioactive-rich sedimentary environment.
diamond; carbonado; Espinhaço range
