Sinitsyn (18 May 1939 – 27 December 2014) was a Soviet/Russian geologist, geochemist and philosopher.
Through the re-examination of exotic rocks that had been discovered but neglected by other geologists, Sinitsyn identified these rocks as kimberlites and that the Archangel region of the Soviet Union was diamondiferous.
Based on this research he led teams that discovered the Lomonosov and Grib diamond mines, the latter considered to be one of the largest diamond mines in the world.