Moissanite vs Cubic Zirconia: what is the real difference?

Where I would actually buy: Charles and Colvard direct for the stone, or Brilliant Earth / James Allen for ring settings. Etsy has great independent jewelers but vet reviews carefully. Amazon is risky unless it is an authorized C&C dealer. Avoid anything under 200 dollars for a 1ct Forever One.

On testers: most standard diamond testers read moissanite as diamond. This is a known issue because both have high thermal conductivity. Testers marketed as 'moissanite detectors' exist but most jewelers do not carry them. A trained eye with a loupe can spot double refraction.

It is cheap because supply is infinite and there is no mined scarcity premium. Natural diamonds are artificially kept expensive by De Beers-style supply control. Moissanite is a manufactured crystal produced in bulk. The 'catch' is not quality, it is simply that there is no prestige premium attached.

Yes, moissanite rings can be resized as long as the metal band is plain gold, platinum, or silver. The stone itself is not harmed by normal resizing. What cannot be resized: full eternity bands with stones all around, and very thin tension settings. Cost is 30-80 dollars.

Double refraction means light bends twice as it passes through, so you see doubled facets when you look through the stone. This is unique to moissanite among common lookalikes. It is invisible face-up and only matters to gemologists. It does not affect beauty or durability.