Method of manufacturing single crystal diamonds

A method of manufacturing a plurality of single crystal diamonds, the method comprising: locating a first and a second single crystal diamond substrate on a carrier, wherein each single crystal diamond substrate comprises a growth surface lying within 15° of a {100} crystallographic plane and edges lying within 15° of a {100} crystallographic plane, wherein the first single crystal diamond substrate is separated from the second single crystal diamond substrate with a centre-to-centre separation perpendicular to a {110} plane relative to a longest edge length of the single crystal diamond substrate of at least √2 and no more than 2; and placing the carrier and the single crystal diamond substrates into a chemical vapour deposition reactor; and growing a first single crystal diamond and a second single crystal diamond on the first and a second single crystal diamond substrates respectively. A sum of an area in plan view of the diamond substrates may define a total diamond substrate area; a sum of an area in plan view of the grown single crystal diamonds may define a total grown diamond area; and the total diamond substrate area may be between 45% and 60 % of the total grown diamond area.