As per the American Kennel Club, blue and tan and blue and gold are the standard colors of the Yorkshire terrier. Yorkies are born black and tan and might eventually dilute and turn blue or gold or both together, depending on the graying gene. However, an all-blue Yorkie puppy is rare.
The Yorkshire terrier could have a blue coat from birth if they inherit two copies of recessive genes from both their parents. However, the blue puppies have an extremely short lifespan and rarely survive up to their adulthood. In case they do, most of their coat color could be seen fading off, acquiring a leathery texture.