Amer - Would be interesting to see the "naked" dial. It is possible that the UV from the lights in your display case or sun exposure (if the watch gets that where it sits) could have caused the crystal to yellow during the time you had it. With the exception of LEDs, all lights give off some amount of UV. If the crystal was prone due to age, and yellowed, it could have cause the effect people are talking about. It is also possible that UV could cause some discoloration of the white sub-dials as well. It's a beautiful piece - good luck with your sale! Jeff