color is pretty important. don't sacrafice a whole bunch there. her friends will be able to see the color just during casual conversation. sacrafice some on the cut and then clarity if you need. buy a simple band/ring to go w/ it. she can always upgrade this later if she wants something more interesting. maybe would make a nice 5th anniversary gift! good luck.
Hate to disagree with goE founding father Rick Daris, but I have it on good authority (Canadian friend) that
cut is the most important of the four Cs. You want "ideal" or "very ideal" or whatever is the best, and that can hide some of the other stuff if it has too. (Although you shouldn't have to hide anything,
) I'm not saying color isn't important, but it's the cut that makes the diamond most sparkly. Definitely think the diamond separate/simpler band idea is a strong one, the band is easy to change.
I bought Mrs. WonderMeal's ring from BrilliantEarth.com, which was really easy to use, all GIA certified, and all of their diamonds are conflict free. (Most come from Canada, like my Canadian friend.) She'll appreciate the bling and the fact that she can rest assured knowing that her diamond wasn't mined by someone who had their feet and hands cut off shortly after working a 19 hour day in the mines. A bunch of my EMAW buddies (I see you, SkinBen) have since used Brilliant Earth on my recommendation, and all have been very happy with it.
Also, this is personal preference, but I think gold or white gold is the way to go. Platinum seems kind of like a fad, and also just looks like silver or steel or something to me. But hey, we're all EMAW fans here, so different strokes for different folks
.