16 CFR 23.16 - Misuse of the words
It is unfair or deceptive to use the unqualified expressions “brilliant,” “brilliant cut,” or “full cut” to describe, identify, or refer to any diamond except a round diamond that has at least thirty-two (32) facets plus the table above the girdle and at least twenty-four (24) facets below.
Note to § 23.16:
Such terms should not be applied to single or rose-cut diamonds. They may be applied to emerald-(rectangular) cut, pear-shaped, heart-shaped, oval-shaped, and marquise-(pointed oval) cut diamonds meeting the above-stated facet requirements when, in immediate conjunction with the term used, the form of the diamond is disclosed.
Title 16 published on 2014-01-01
no entries appear in the Federal Register after this date.