What is the downside of moissanite?

Moissanite has four main downsides: stronger rainbow fire than diamond (which some find too flashy), a double-refraction effect visible under magnification, lower resale value than mined diamond, and a color tint in larger stones that reads slightly warm under certain lighting.

The most commonly cited issue is moissanite's fire — its dispersion rating of 0.104 is roughly 2.4 times diamond's 0.044, which produces vivid rainbow flashes rather than diamond's subtler white brilliance. In smaller stones, that reads as lively sparkle. In larger moissanite stones — generally above 2.0 carats — the rainbow effect becomes more pronounced and is the clearest visual signal that the stone is not a diamond.

• Moissanite dispersion rating: 0.104 versus diamond's 0.044 — roughly 2.4x more colorful fire.
• Moissanite refractive index: 2.65, producing a double-refraction effect visible under 10x magnification.
• Rainbow fire is most noticeable in moissanite stones above approximately 2.0 carats.
• Moissanite carries near-zero secondary market resale value compared to mined diamond.
• Near-colorless moissanite (GRA grades DEF) minimizes warm tinting; lower grades may show a faint yellow or gray cast in certain light.