I'm actually going to be testing with moissanite on some new things. It's refractive index isn't precisely the same but it's close enough to get the idea.
Piggybacking off this cos I've wondered for a while - are melee and other teeny stones cut by hand? I assume yes but I also wouldn't be too surprised if there's a way to do it with machines.
If they are cut by hand, how on earth does the cutter keep track of all the tiny sparkles? I recently got a ring of tiny french/mixed cuts unset and trying to work out how many I had of each cut while peering through a loupe was hilariously difficult to stop them pinging off everywhere.
I've seen video of bigger stones being cut and that's amazing. It's even more amazing if it's the same for the little stones too.