Honestly Anne, were it completely up to me, that rock would be a part of our mortgage payment. Unfortunately, while my wife is very intelligent, she's also had a vision her whole life of how marriage is supposed to go, and part of that is the ring. I don't understand the fascination myself (there's far prettier, cheaper and more unique stones available), but I understand that the fascination exists and how important it is to her and I just can't take that away from her.
As to the appraised value, it's about 1k higher than the 'sum of the parts'. I did my research and bought the stone separately based on the characteristics I thought most important (cut, clarity, color, and carat, in that order) from a diamond broker. It was then independently appraised and ceritfied (or it would have been returned). I had it mounted in a temporary setting, then afterwards I went shopping with my fiance at the time for the right setting. After re-mounting, the whole ring was again appraised, and this was the value used for insurance. We had it insured under a renters policy previously at $55/month, but had to move the policy. First quote was $70/month, but I'm still shopping.
Incidentally, anyone looking for a good book on diamonds should read How To Buy A Diamond: Insider Secrets For Getting Your Money's Worth
by Fred Cuellar. That book kept me from making alot of costly mistakes. It's got a good section on the mathematics behind how diamonds are cut and the associated light dynamics, and let a math dork like myself find something objective in a primarily subjective topic. It also allowed me to know instantly just based on the diamond certification whether a broker was trying to show me a 'lemon'. I brought the book with me to the first broker I met with and he groaned and said, "oh no another engineer".
Dangit, rambling again!