Crystal growth of diamond in the system of carbon and water under very high pressure and temperature

Diamond grew considerably with a weight increase of about 70% on a natural octahedral diamond of about 2 mg weight embedded in a graphite capsule with a small amount of water at high pressure and temperature of 7.7 GPa and 2200°C for 17 min. Although much graphite was included in the grown diamond, epitaxial growth was realized with the layer growth patterns on the surface and the tightly bonded boundary between the newly grown region and the seed crystal.