While it is true that only a D grade diamond is truly colorless, most people would have trouble seeing any color in D, E or F grades. Also, even the best diamond graders might disagree by one grade, so it’s a little indefinite. And if the diamond is set, particularly in yellow gold, it will reflect a little of the gold color, thus disguising the true color grade. An appraiser would not attempt to pin down the color of a diamond mounted in yellow gold beyond an accuracy of plus or minus one color grade, maybe two. So if you are buying to wear or give, the best advice is to compare various diamonds and pick what looks attractive to you. You may find that you don’t see or don’t mind or even prefer a little color.