Lots of people are pretty into treating gems and rings as separate goods, or want grandma's diamond in a new ring. So I don't think getting them separately will

Lots of people are pretty into treating gems and rings as separate goods, or want grandma's diamond in a new ring. So I don't think getting them separately will be an issue. But I'd definitely consider looking up shiny precious gems on Reddit - for less money than a diamond you can really get some nicely cut and much more interesting Sapphires.