Rotor plate ruby pinion question ???

I had my Seamaster opened by a local shop recently and I noticed that the movement contains a ruby in the center of the pinion that the rotor is attached to. You can see it in the attached photo with a circle around it. First of all, I'm happy that mine still has that part as I noticed that almost all of the Omega movement images I've seen, that part is missing. Can someone tell me what is the significance of that part? Is it just cosmetic or does it actually serve a purpose? I'm going to have mine serviced by Omega, should I make sure that they replace it or at least, put it back if they can't find an exact replacement?

So that ruby colored center is lubricant? I didn't know that the lube they use is ruby red? It's strange that it looks perfectly shaped too. Nice and round.