there is a color discrepancy between the mental die, and the ungimmicked dice. The mental die is the
slightest bit less white, a darker color.
You have to look at them next to each other to
see it, but it is a distinct enough difference that in good light I notice it every time.
I
don't have to look at the 6 and 3 to know which die it is at a quick glance.
I don't know
what to recommend except don't show the two together.