Which of the following is a characteristic of gemstones with deep pavilions?

Deep pavilions in gemstones lead to higher extinction due to the geometry of how light interacts with the stone. When a gemstone has a deep pavilion, light entering the stone is more likely to be absorbed or reflected at angles that do not allow it to escape back out of the gem. This results in a reduction of the light that can be seen when looking through the table of the stone, leading to a darker appearance and higher levels of extinction.

In contrast, shallower pavilions tend to allow more light to exit the gem, increasing brilliance and reducing the extinction effect. The other options relate to aspects like brilliance or windowing that would not inherently connect to the depth of the pavilion in the context of light performance. Thus, the defining characteristic of deep pavilions is their tendency to contribute to higher extinction.