 Do you mean the stained glass mirrors? Glass doesn't change colour with age (except for clear glass, which can yellow). What statue are you talking about? Ahh, I thought they were statues for some reason. I always figured that the coloring must have been preserved purposefully not only with Rhea's descendants, but also the other women who were captured with her. It just seems odd that the royal family would have this coloring, but hardly anyone else in Andor. So if it wasn't already a royal family trait at the time of Ishara, then perhaps it was bred in later. But it does indicate selective breeding. I think there might be a lot of relative inbreeding in the royal family due to the way Andor judges strength of claim. Like, marrying third cousins and whatnot.  