can you get a sample sent to you from the manufacturer or whomever will be fabricating your top (they make small ones that are like 3" squares in cambria)? even if postage to you is relatively expensive, it's way less expensive than hating your tops once they are installed.

If you are afraid your quartz countertop will be too grey, maybe you should try to go with something like Frosty Carrina or London Grey.