An I1 diamond exhibits visible inclusions under a 10X jeweler's loupe, which means it is included to the first degree. I1 diamonds are not eye-clean since I1 inclusions are also virtually always visible to the unaided eye. "Evaluating diamond clarity requires identifying the quantity, size, relief, type, and location of these qualities, as well as how these impact the overall look of the stone," the GIA laboratory said. We have learned from decades of experience that an I1 diamond won't be eye-clean until it weighs less than 0.5 carats. Because it is easier to spot flaws in bigger stones, no larger diamond will be eye-clean at an I1 rating. It's possible that there are a few exceptions to this rule, but they are uncommon.