Hi Aroh,
Seems that you have been a close follower of Fann wong news. lol. Think she's holding her wedding at either Shangri-La or Ritz Caltron. Im speculating to be the former though. Just my guess. =P
As for diamond, for a $50K 2 carats diamonds... it an average one we are looking at.... probably not the best colour at D, best clarity at IF/ FI, not the best cut and proportions of diamond. A good quality of 2 carats can go up to as high as $100K and above. So there is something in the 4Cs that Fann or should I say Christopher have compromised on. Take a walk to the Jewelers say Je Taime or Larry, you'll figure out the sums vs quality. =)
Anyway, end of day, it an expression of love from the spouse... irregardless of the size and quality.. so really there's no need for comparisons. =)