When I made the mistake, I mean got engaged, I bought the stone separate from the ring. Did my home work on the 4 C's (cut, color, clarity, carat). [url]http://www.gia.org/gemsandgemology/357/ig__gi_indexes.cfm[/url] Look under how to buy a diamond.
Long story short I paid $1800.00 for a .99 carat SI1 H-Color stone in 1996. Had it set in a 4 prong Tiffany setting until the wife decided what the permanent setting would be. Later we mounted it in a platinum "fishtail" setting (Makes a round stone look square) with 2 .25 carat beggette (sp?) stones. Total investment was $3100.00 Throw in my grandmothers platinum eternity band and I had total of 2 carats. The set appraised at $8500.00 after it was done. ($7000 without the eternity band). Set a CZ in the original Tiffany setting and got her a inexpensive gold band to go with it for every day wear to work to get beat up. Wore the real thing for occasions other than daily use.
Then I lost it in the divorce last year. (I didn't care so much about the big stone I bought, I just wanted my grandmothers ring back).