Lab Grown Diamonds are optically and chemically identical to Natural diamonds.  The process begins with a diamond "seed" that is exposed to high temperatures .  A carbon coating is added to help the diamond crystallize as it grows.  They are indistinguishable from natural diamonds when viewed under a professional jeweler's loupe. Lab Grown Diamonds are classified by GIA as either "Premium" or Standard based on an overall assessment of color, clarity and cut.