What is girdle thickness and why does it matter for durability?

• A. It is the color grade around the girdle; it does not affect durability.
• B. It refers to thickness around the widest point and extremes can increase chip risk or affect weight.
• C. It is the depth of the culet; this controls transmission.
• D. It measures the girdle's reflective properties.

Answer: (B)

Girdle thickness is the width around the stone at its widest point. This matters for durability because extremes have direct effects: a very thin girdle is more prone to chipping along the edge if the gem is bumped, while a very thick girdle adds more material and weight around the perimeter, which can influence how the stone wears, balances in a setting, and its perceived proportions. The statement that girdle thickness refers to the widest-point width and that extremes can increase chip risk or affect weight captures both what the feature is and how it impacts durability.

Other options describe unrelated aspects: color grading around the girdle, the culet’s depth, or the girdle’s reflective properties, none of which define girdle thickness.