Moissanite is one of the hardest, toughest and more durable substances on earth. It is as atomically stable as a diamond, and in some ways even moreso (i.e. it can withstand greater heat than diamond). Therefore its impossible for it cloud, dull or fade with time. It is the type of heirloom gemstone that can be passed down from generation to generation and look just as brilliant as the day it was first purchased.
Charles & Colvard provides a warranty on the optical properties of Moissanite gemstones. Since the properties of moissanite are inert, and can never change, the warranty is offered as confirmation that moissanite will retain its properties forever. In over a decade of selling C&C Moissanite, we have never experienced a single incident of Moissanite fading, going dull, etc. except through getting dirty or damaged. It is expected that there will never be an instance where a warranty claim would be necessary.
Like all such warranties, the C&C warranty does not cover abuse or damage to the gemstone. Click here to view the C&C warranty card. To protect your Moissanite gemstone and jewelry against damage we would recommend obtaining jewelry insurance.