[LunarBerry]

I've read up on this a little while back but am not sure how accurate it is. I've heard that if the shine in their eyes reflects back blue/green, they have silky coat, but if it's red/orange-ish it's cotton. I've also heard otherwise sometimes. Another describes cotton coated yorkies, as yorkies that look bigger than they are and sometimes the coat is a little curly/wavy. Silky coats were described as fine and just hangs straight down.
My girl seems to fit the cotton coat so far in just about all way, but that might change when she gets older, cause I also hear you won't know for sure till their coat fully matures.