Trixie   7 months old

This breed comes in just about every color and pattern you care to imagine, in either long or short coat

Chihuahuas come in many colors, from solid blacks to solid whites, spotted, or a variety of other colors like fawn (tan), chocolate, blue (gray), silver, tricolored (chocolate, blue, or black with tan and white markings), brindle, and merle. And each of these colors vary in shades and tones, as fawn can be a term to describe a tan dog from a very pale cream to a deep (almost red) tan, or any shade in between, and the chocolate coloration can range from a milky light shade of brown, to a deep mahogony brown, to a dark brown that is almost black.

Combinations of genetic variance that  produce kind of grey that appears to have a tinge of blue in it.
You can get a blue Chihuahua from a black and tan, a chocolate, or even a fawn parent. Obviously, to get a blue Chihuahua, the parents must have a recessive blue gene in their heritage, even if it is some way back in the line. 

                                 Blue Chihuahuas are very rare.

These dogs are very expensive and show quality individuals with rare coat colors can reach up to $3000.

                                               Amigo 6 months old