Hi there, hope you are enjoying BYC!
Yes, that is indeed an ear lobe. The blue is likely a Silkie cross on that girl. I don't know of any other breeds with blue lobes.. and it might be one of my favorite Silkie characteristics!
Other possible lobe colors are red, white, and kinda cream (between red and white). Usually white lobes means white eggs. Red lobes often means some shade of brown eggs but it can be blue or olive. Cream ears cream layer. These are generalizations and may not always be the case.
Oh... and after breeding Silkies for a few years (previously), who lay cream colored eggs.. I strongly believe the blue lobe is a side effect of the white wash on the dark skin.