Moissanite is a gemstone made of silicon carbide (SiC) that closely resembles a diamond in appearance but has distinct physical and optical properties. Originally discovered in 1893 by Henri Moissan, a French chemist, moissanite was first found in a meteorite crater and was initially mistaken for a diamond. Natural moissanite is extremely rare, so all moissanite gemstones available in jewelry today are lab-created.
Moissanite vs. Diamond – Key Differences
Property Moissanite Diamond
Composition Silicon carbide (SiC) Carbon (C)
Hardness (Mohs Scale) 9.25 (very hard, second only to diamond) 10 (hardest natural material)
Brilliance (Refractive Index) 2.65–2.69 (higher brilliance than diamond) 2.42
Dispersion (Fire) 0.104 (more fire, creating rainbow flashes of light) 0.044
Toughness Excellent Excellent
Price Much lower than diamond Higher, especially for natural diamonds
Rarity Lab-created Natural or lab-grown
Fluorescence May have faint fluorescence Can range from none to strong
Ethical Considerations Conflict-free, eco-friendly Natural diamonds may have ethical sourcing concerns
Moissanite’s Optical Properties
One of the most notable differences between moissanite and diamond is its higher refractive index (2.65–2.69), which results in greater brilliance and fire (the dispersion of light into rainbow colors). This makes moissanite appear more sparkly, especially under bright light.
Some people find this extra fire appealing, while others prefer the more subtle, pure white sparkle of diamonds.
Durability and Hardness
Moissanite is extremely durable, with a Mohs hardness of 9.25, making it the second hardest gemstone after diamond (10). It is resistant to scratching, making it an excellent choice for engagement rings and everyday jewelry.
Price and Affordability
Moissanite is significantly more affordable than diamonds of comparable size and quality.
A 1-carat moissanite costs a fraction of the price of a 1-carat diamond.
The cost does not increase exponentially with size, as it does with diamonds.
Moissanite as a Diamond Alternative
Because of its brilliance, durability, and affordability, moissanite is a popular alternative to diamonds, particularly for engagement rings and fine jewelry. Many people choose moissanite for its ethical and eco-friendly benefits, as it is lab-created and does not involve mining.