my girlfriends diamond ring has 3 diamonds that glow under a blicklight. why? fake?(better not be i paid 2 grand for it)

It'* not really glowing. It'* refracting off all the facets of the stone. There might even be some adhsive/epoxy holding the stones base in. It might be that, then that glow is refracted through the stone.

I don't know diamonds, but I know refraction/light, etc.

Glowing under blacklight means they are diamonds and not CZ, but not very good diamonds.