Assertion: stone's color | /r/HasProperty | judged by trained human eye
Facets:
Source sentences:
text: There are two major non-profit gemological associations which grade and provide reports, (informally referred to by the term certificate or cert, which is a misnomer for many grading reports) on diamonds; while carat weight and cut angles are mathematically defined, the clarity and color are judged by the trained human eye and are therefore open to slight variance in interpretation.