To obtain a particle abrasive of minute single crystal diamond that has mechanical strengths characteristic of diamond, a particle surface coated with non-diamond carbon formed by conversion from diamond and ≤5 μm average particle diameter.

The surface-modified minute diamond abrasive comprises bringing diamond particles formed by static ultra-high pressure synthesis and having ≤5 μm average particle diameter (D50 value) into close contact with an iron group metal or an iron group metal oxide, heating and keeping the diamond particles in a nonoxidizing atmosphere at <1,000°C treatment temperature to partially convert the surfaces of the diamond particles to non-diamond carbon.