A term used to imply that no internal flaws are visible to the unaided eye of a qualified diamond-clarity grader. It is prohibited by the American Gem Society for use by its members. It is also prohibited by the Federal Trade Commission, unless the stone meets the Commission's definition of the term perfect.

A way of describing a gemâ€(tm)s lack of visible inclusions when inspected only by the eye, without the assistance of magnification.

A term used in the industry to describe a diamond with inclusions that cannot be seen with the naked eye.