What is the term for a diamond with no visible inclusions to the naked eye?

The term "eye-clean" refers specifically to a diamond that has no visible inclusions when viewed without magnification. This designation is based on the fact that even if minor inclusions exist in the diamond, they are not perceptible to someone examining the stone with the naked eye.

Being eye-clean is a highly desirable attribute in diamonds, as it suggests a certain level of quality and visual appeal. Many buyers prefer eye-clean diamonds, particularly for engagement rings or fine jewelry, because they tend to present a more flawless appearance despite possible minor inclusions that could only be detected under magnification.

In contrast, the other terms listed, such as "flawless" and "perfect clarity," imply a higher standard, indicating a diamond with absolutely no inclusions or blemishes even under magnification. "Inclusion-free" might suggest a similar idea to "flawless," but it is not a commonly used term in the grading of diamonds. Therefore, “eye-clean” is the most accurate and appropriate term for describing diamonds that appear immaculate to the naked eye.