A colored stone that rates "fair" for brilliance has what percentage of brilliance?

In the context of assessing colored stones, brilliance refers to the amount of light that reflects back to the viewer's eye from the stone. When a stone is rated as "fair" for brilliance, it indicates that the light return is moderate but not particularly high, suggesting that the stone has some reflective qualities, yet lacks the ideal levels found in higher-rated stones.

The range of "25 to 40 percent" for brilliance accurately correlates with this classification. Stones falling within this percentage can display an acceptable amount of light return, making a positive impression without reaching the optimal levels of brilliance that occur in stones rated higher. Ratings are essential in grading the visual performance of colored stones, influencing both aesthetic perception and market value.

Understanding these grading ranges allows gemologists and enthusiasts to evaluate and communicate the qualities of colored stones effectively, helping buyers make informed decisions.