Which term defines the angles and relative measurements of a polished gem and the relationships between them?

Which term defines the angles and relative measurements of a polished gem and the relationships between them?

• A. Relief
• B. Refraction
• C. Proportions
• D. Refractive index (RI)

Answer: (C)

Proportions describe the angles and relative measurements of a polished gem and how those dimensions relate to one another. In a cut gem, the table width, crown angle, pavilion depth, girdle thickness, and other facet angles all come together as part of its proportions. This overall balance determines symmetry, brilliance, and how light is returned to the viewer, making proportions the best term for describing the gem’s geometric relationships. While refraction and refractive index focus on how light bends through the material, and relief concerns how facet depths affect light leakage, neither captures the complete set of geometric relationships that proportions describe.

Proportions describe the angles and relative measurements of a polished gem and how those dimensions relate to one another. In a cut gem, the table width, crown angle, pavilion depth, girdle thickness, and other facet angles all come together as part of its proportions. This overall balance determines symmetry, brilliance, and how light is returned to the viewer, making proportions the best term for describing the gem’s geometric relationships. While refraction and refractive index focus on how light bends through the material, and relief concerns how facet depths affect light leakage, neither captures the complete set of geometric relationships that proportions describe.