18ct white gold round brilliant cut diamond lab grown diamond four claw set pendant on an 18" chain. 0.74ct diamond, D colour, Si1 clarity. A lab grown diamond is a real diamond that is grown in a laboratory rather than naturally within the Earth's core, it has the same chemical and physical structure as a natural diamond. The main difference between lab grown and natural diamonds is the origin and rarity. To find out more information about lab grown diamonds please read our blog.