Uncut octahedral diamond crystals. Uncut octahedral diamond crystals. Round brilliant cut. Diamond engagement rings. Highly reflective areas on lap are where stone is being polished.
Dull areas are where stone is being shaped.
Highly reflective areas on lap are where stone is being polished. Dull areas are where stone is being shaped. Open pit diamond mine is South Africa. For Further Reading Gubelin, E. J., 1974. Dana's Manual of Mineralogy, 17th Ed.