This is what may go through her mind when you give her the rock:

On the other hand, let’s look at the alternate scenario where he gives her a DeBeers white diamond:

"Oh my gosh he is finally proposing....its a....a......A F^@%ING DEBEERS WHITE DIAMOND! THAT F^@%ING HYPOCRYTE! WE TALKED ABOUT NON-TRADITIONAL RINGS! HE SHOWED ME THAT FREAKING ARTICLE ABOUT DEBEERS! THAT A$$HOLE! NOT ONLY DOES HE NOT LISTEN TO ME, HE DOESN'T EVEN FOLLOW THROUGH ON HIS OWN ADVICE! I can't take this....no.....no...I'm not going through with it, no way can I marry this a$$hole. Of all the....."

Sounds to me like he made the right choice.

Good luck man. Hope she says yes and hope she keeps saying yes for the rest of your lives! : )