What are Masterstones?

What are Masterstones?

• A. A set of color-comparison diamonds that defines GIA diamond color grades in the normal (D-to-Z) range.
• B. A type of synthetic diamond
• C. A tool for measuring carat weight
• D. A solvent used in cleaning

Answer: (A)

Masterstones are a set of color-reference diamonds used to calibrate and standardize diamond color grading within the normal D-to-Z range defined by GIA. Each Masterstone has a known color grade, and graders compare a diamond under standardized lighting to these anchors to determine its color grade, ensuring consistency across different evaluators and laboratories. They are natural diamonds selected for fixed color positions, and they relate to color assessment rather than weight or cleaning.

Masterstones are a set of color-reference diamonds used to calibrate and standardize diamond color grading within the normal D-to-Z range defined by GIA. Each Masterstone has a known color grade, and graders compare a diamond under standardized lighting to these anchors to determine its color grade, ensuring consistency across different evaluators and laboratories. They are natural diamonds selected for fixed color positions, and they relate to color assessment rather than weight or cleaning.