Figure 5 shows observers under 30 years of age (top and center) examining the three diamonds resting in their fingers. On the lower row an older observer is examining the stones. On the center right is a dome used by the GIA to replicate the Diamond Dock 'brightness' lighting.

Younger observers preferred the 'ideal' (B) followed by the deep stone (C). Older observers preferred the shallow (A), followed by the 'ideal' stone (B). The dome in Figure 5 was used by the GIA and has a central peep hole and a dark area that mimics 46° obstruction of the available 180° of illumination.

Figure 5. Observers of different ages (young, top and center and older, lower) examining the three diamonds resting in their fingers. On the center right is a dome used by the GIA to replicate the Diamond Dock 'brightness' lighting.