system
A chat on subreddit /r/me_irl
human
You can definitely, quite easily, distinguish moissanite from diamond, though. Moissanite is much more brilliant in general and has a rainbowy brilliance which I love but it's what turns some people off of it.

Imo though moissies are far superior than diamonds in every way.
gpt
Ah, yeah, for sure you can see more fire in moiss and if you have a magnifying glass and not the tiniest stone ever, you can distinguish the birefringence.

For me as well, moiss are better, and objectively you can say only that its hardness on mohs scale is smaller than a diamond's. But tbh, its still something higher than corrundum so Im not sure in which situations you're gonna get it scratched (maybe by another diamond or idk).

But, with all of these points stated, for suresies there is still someone that will throw a moiss when he finds out its not a "natural diamond".