Welcome to YT!! You have a beautiful pup - hopefully we can see some more pictures soon!
There are many different stages that yorkies go through. How old is yours? Both Darwin and Mabel seem to be going through changes - so far they remain black & gold. Darwin just turned 2 and is just now starting to get a touch of grey showing on his sides. Mabel is 1 and is still black and gold. About 4-6 months they started getting gray on their heads but it soon turned to a beautiful gold colour. Kind of like Christmas, one surprise after another!