What does extinction in a gemstone result from?

Extinction in a gemstone refers to the loss of light that occurs when certain parts of the gem block light from entering or exiting. This phenomenon is significantly influenced by the pavilion depth of the gemstone. A deep pavilion can lead to increased extinction because it affects how light interacts with the stone. When the pavilion is too deep, light may not return to the surface effectively, often resulting in dark zones or areas where the gem appears lifeless.

In contrast, a shallower pavilion might allow more light to enter and exit the gemstone, thereby enhancing its brilliance and overall appearance. Additionally, while high polish can improve the play of light, it does not directly influence extinction; poor cutting could lead to various issues, including improper light return, but the primary factor in this case is the depth of the pavilion. Thus, deep pavilions are directly related to the phenomenon of extinction in gemstones, making it the correct answer in this context.