Which statement accurately describes the Master-Eye Effect?

• A. It measures the stone's carat weight.
• B. It causes the ungraded diamond to appear lighter or darker depending on which side it's on.
• C. It is used to determine fluorescence.
• D. It defines the color grade range.

Answer: (B)

The Master-Eye Effect is about how lighting and orientation can change how a diamond’s color looks during grading. When an ungraded diamond is viewed under standardized lighting against a reference color (the “master” standard), flipping the stone so a different side faces the viewer can make it appear lighter on one orientation and darker on another. This perceptual shift happens because the way light enters, travels through, and reflects in the diamond changes with facet arrangement and the reference background. Graders use this awareness to keep orientation and lighting consistent, ensuring color assessments are reliable. It’s not about carat weight, fluorescence, or defining the color range.