Memorial diamonds are diamonds created from hair or cremated remains.
Typically, these are diamonds created in a laboratory, often referred to as "synthetic diamonds", "cultured diamonds", or "laboratory-grown diamonds". Some memorial diamonds are graded by gemological laboratories, such as Gemological Institute of America (US) or Birmingham Assay Office (United Kingdom).
Memorial diamonds are produced from hair or ashes, with other carbon ("lab carbon") added as necessary.
In case of hair, it is subjected to heat treatment to extract carbon. Some laboratories also analyse content of hair. A hair analysis report then serves as a client assurance.[clarification needed] The process of unique identification of a diamond and a person based on the hair composition is described in the diamond patent RU2282584 
Carbon can be obtained from cremated human or animal remains in a particulate or gaseous form. The carbon is then filtered using a conventional filtering technique. The carbon and other elements are then purified and graphitized, for example by a halogen purification technique. 
The diamonds are then produced from the carbon extracted using conventional diamond synthesis techniques. As of 2009, only high pressure, high temperature (HPHT) processes using belt and cubic presses were used for the production of memorial diamonds.