Tabby and Silver Chinchilla mix cats are generally considered quite attractive. They might exhibit the gradient colors of a Chinchilla, or they could have the body type of a Tabby with the coloration of a Chinchilla.

What Do Tabby and Silver Chinchilla Mixes Look Like?
One possibility is that they inherit the gradient color of the Chinchilla, with the tabby's stripes and patterns. The hair root might be dark, while the tips transition into the Chinchilla's gradient hue, resulting in a harmonious and pleasing appearance, often referred to as a "chinchilla tabby". Another possibility is that the cat could have the tabby's body type and stripes, but the gray coloration of a Chinchilla. The third common appearance is having a Chinchilla's body type and markings with the Tabby's colors. In this case, they might be predominantly black, like a black Chinchilla. There are many possibilities with the genetic recombination of two different breeds. Each kitten will be unique.
Is a Silver Chinchilla with Tabby Markings Impure?
A Silver Chinchilla with tabby markings is not impure. The presence of tabby patterns on the coat and limbs of a silver Chinchilla is actually an uncommon throwback to their ancestry. The Silver Chinchilla is a color variation, usually associated with the British Shorthair. So, pet owners can rest assured that their cat is not impure. Instead, they have a rare and interesting trait within their genetic makeup.
It is important to understand that breed standards sometimes mean that cats with less common color patterns are not show standard, but this does not mean they are not purebred.