How would you feel if you got a gemstone engagement ring as opposed to a diamond?

I'm not that serious with my boyfriend yet, but he was asking me what sorts of gems I liked and he thought it was interesting that I preferred emeralds over diamonds. So it made me think, if it ever got that far, what if I received a proposed with a gemstone engagement ring instead of a diamond one? I think it would be kind of neat and different, but I just wondered what other people thought of it. I am just curious, my boyfriend hasn't even told me he loved me but with the royal wedding going on and that sapphire engagement ring and then him asking me what sorts of stones I liked (probably for more like earrings and whatnot) just piqued my curiosity.