Clarity refers to the imperfections (blemishes, scratches, nicks, etc. . . .) in a diamond, and experts use the scale I1 to IF (internally flawless) as a measurement tool. So what's the sweet spot for deciding on the clarity of your ring? Depending on your finances, anything from SI1 and up is the best. "Never in my years have I ever recommended a friend to buy an internally flawless diamond, but we sell a lot of them because there are some consumers that love that concept," Dean said. "There is no right or wrong answer in buying a diamond. And that's why for [some] it's torture and that's why it's wonderful when [their partner] is willing to collaborate on it."