Ok IMHO you spent the dough on a friggin' diamond ring, now it's time you get her something that has sentimental meaning and value. Who cares if it's $30 or $300. Meaning behind a gift is priceless. And if that's what you're going for, then you just gotta dig deep and think of something that's truly awesome. I mean you can get her that ruby, pearl, sapphire ring on your first year anniversary or your 50th.
And if all else fails, get her a nice ring (bring a girl friend or metro guy friend) and get her a ring with her birthstone (the setting is the most important), engrave it and she'll be happy.
OR
get a literal rock set on a ring and give it to her
LOL