Merle is not a color…it is a color PATTERN.  A Yorkshire Terrier of any color can carry a special gene (allele) that makes a dog a Merle even if you cannot actually “see” it’s a merle pattern.  If the Merle allele is allowed to “express” itself, merle is characterized by irregularly shaped patches with deluted pigment while other patches on the coat are fully pigmented.  The color portion of the eye can be diluted, giving a blue or partially blue color to the eye; when this occurs in Yorkies, you often hear that Merle described as a “Blue Diamond” Merle.  Pigment on the nose and foot pads can also be diluted, giving a mottled appearance.  NOTE: Breeding Merles is dangerous; it should only be done by knowledgeable and experienced breeders who test their dogs for cryptic (hidden) merle because a puppy born with 2 merle genes is often “doomed” to deafness, blindness, heart and/or other birth defects that can result in death of the puppy.  It is critical that buyers comply with our “No Breeding” contract for the safety and welfare of their pet or Service dog.