The stone itself stays clear. Moissanite is silicon carbide, which is dense, unporous and chemically settled, so it has nothing to absorb and nothing to oxidise. A piece you wear every day for years will be the same stone at the end of it.
So why does it sometimes look dull
Because something is sitting on it. Hand cream, soap that was rinsed in a hurry, the oil your own skin leaves, hairspray, the fine film that builds up when a piece is worn daily and never wiped. It gathers in the same places every time: underneath the stone, where the setting meets it, and along the girdle.
Moissanite shows this sooner than a duller stone would, and for a flattering reason. It returns more light than a diamond does and more than twice as much colour, so it depends on light entering cleanly from below. A film across the pavilion stops that light before it starts, and the fire goes quiet. The brilliance is still there. It is simply being blocked.
How long it takes to come back
A few minutes in warm water with a drop of washing up liquid, and a soft brush along the underside. Rinse, dry with a lint free cloth, and the stone is as it was. We have written out the whole method in how to clean moissanite.
One thing worth knowing about the setting
Every Clariva piece is moissanite set in 925 sterling silver beneath a gold tone finish that is waterproof and tarnish resistant. That finish is the part to be gentle with. Warm water and a mild soap suit it; harsh chemicals and abrasive pastes are best kept away from it, which is true of any plated jewellery.
The short answer
Moissanite does not cloud. It collects a film, like every stone worn against skin, and it gives the light straight back the moment the film is gone.
The piece this was written beside
The Celestine Pendant, $143.99. Moissanite set in 925 sterling silver beneath a waterproof, tarnish resistant gold tone, on its chain, with tracked delivery included.