My two cents...
I came about
this close to buying from an online dealer that I had researched thoroughly. The guy spent total, probably 3+ hours on the phone with me over time and faxed me countless certifications for me to look at. I felt totally comfortable with him and if I made a purchase from him could have had my own certification done and if I wasn't happy with the stones I could have gotten a full refund no questions asked. I would highly recommend
that guy.
That being said, I had a local wholesaler recommended to me that happened to be in my office building at the time and I didn't even know it. I worked with him over a period of a couple of months looking at different stones until he finally found me
the ones. Then we worked and designed a custom setting for them which he had another jeweler make. And I did go the platinum route and couldn't care less about the softness of the metal. If you want a platinum ring you know the metal isn't going to be impervious. Hell, my wedding band is platinum and looks awesome with scuffs on it. And when I look at my wife's rings I guarantee you it isn't scratches that catch your eye.
All said and done, I probably got twice the ring for the amount of money I wanted to spend. So in sum, find yourself a local wholesaler. Thats the dealio. And I won't talk about stones, that's a personal deal and you'll know the difference when you start looking at them. And do your homework like with any large purchase.