Method of growing bulk single crystal diamond on a substrate in a prescribed gas environment at a prescribed temperature and pressure

A method of forming one or more diamonds, the method comprising:

• providing a growth chamber having a gas environment;
• positioning a single crystal diamond substrate within the growth chamber;
• depositing diamond material on the single crystal diamond substrate for epitaxial growth, the single crystal diamond substrate having a given crystal orientation;
• growing single crystal diamond outwardly on the single crystal diamond substrate at a prescribed temperature, prescribed pressure, and with a prescribed gas content for the gas environment to produce a bulk single crystal diamond,
• the prescribed gas environment having a nitrogen concentration of 2 ppm to 5 ppm for a first growth period,
• the prescribed temperature being greater than 650 degrees C. and less than 950 degrees C.,
• the prescribed pressure being greater than 130 Torr and less than 175 Torr;
• altering the prescribed gas environment to have the nitrogen concentration of 0.5 ppm to 1.5 ppm for a second growth period after the first growth period.