Moissanite

Lab-created Moissanite is a near-colorless jewel made from silicon carbide (SiC) based on natural Moissanite. Naturally-occurring Moissanite is an extremely rare mineral found in limited quantities or as small particles in the earth, so Moissanite that is used in jewelry are lab-grown. Moissanite is a very hard and durable gemstone, second only to diamonds. It has more fire and brilliance than diamonds. 

Moissanite has a RI of 2.65-2.69, fire dispersion of 0.104, and a Mohs hardness of 9.25 - compared with a diamond which has a RI of 2.42, fire dispersion of 0.044 and a Mohs hardness of 10. 

The company Charles and Colvard make three types of Moissanite based on their color rating. Forever One is D-F (colorless), Forever Brilliant is G-I (near colorless), and Forever Classic is J-K (faint). Charles and Colvard are no longer making Forever Classic and Forever Brilliant Moissanite.