At high pressure/high temperature (HPHT) fullerenes collapse is followed by formation of a nanoclustered graphene phase (NGP) that exhibits a remarkable combination of mechanical properties: high hardness, high elastic recovery and low friction coefficient. Residual C₆₀ polymers jeopardize mechanical properties of the NGP therefore a special effort is needed for synthesis of “polymer-free” graphene phase. We recently demonstrated ability to drastically improve mechanical properties of the NGP produced from C₆₀ by controlling the disorder level/graphene clusters size in the system. In this talk we present our study of fullerene-NGP transformation by employing multi-excitation Raman spectroscopy, SEM, High-resolution scanning TEM/EELS and mechanical testing and discus structural model of the transformation.