the scallop will change color as it ages {1-3 yrs} and if they are harvested from various locations.
example scallops from brown's banks tend to be darker in color then ones from inshore (bay of fundy). I have seen this as I once worker on a scallop boats. I not sure just how old a scallop can live. The time of year will also effect the color, right noe the local scallops here have roe and are a bit grey/off white in color. hope this was some help. later ...merwin