BGI's exclusive brilliance grading standard. Light interaction modeling redefining diamond beauty.
Clara is BGI's proprietary and revolutionary brilliance grading standard, the fifth C in the 6C system. While traditional cut grading evaluates facet proportions and angles, Clara directly measures and classifies how a diamond actually performs with light through advanced light interaction modeling and brilliance analysis.
The Clara standard was developed by BGI's research team to address a gap in traditional diamond grading: two diamonds with identical cut grades can appear dramatically different in terms of visual brilliance. Clara captures this difference through empirical light performance measurement.
BGI's Clara grading system uses precision optical instruments to capture and analyze the diamond's light return across multiple viewing angles. The system measures total light performance, contrast patterns, and brilliance distribution, then classifies the result into one of five Clara levels.
This quantitative approach removes subjectivity from brilliance assessment and provides diamond buyers with a clear, objective measure of a diamond's visual impact. Clara grading complements traditional cut grading by capturing the dynamic light performance that static proportion measurements cannot.
Together with the traditional 4Cs and Crypto blockchain certification, Clara completes BGI's comprehensive 6C system. It answers the question every diamond buyer asks: "How beautiful will this diamond actually look?" BGI is the first institution to provide an answer backed by scientific measurement.
| Level | Name | Light Performance Description |
|---|---|---|
| Clara 5 | Ultimate | Exceptional light return with perfect brilliance distribution across all viewing angles. |
| Clara 4 | Exceptional | Superior brightness and fire with excellent contrast patterning. |
| Clara 3 | Excellent | Strong light performance with good brilliance and scintillation balance. |
| Clara 2 | Very Good | Good brightness with moderate fire and acceptable contrast. |
| Clara 1 | Good | Satisfactory light return with standard brilliance characteristics. |
Last Updated: June 2026 · BGI 6C Diamond Standards™