Tarnish

Tarnish is a relatively simple marking. It creates a dark sheen on the coat, like a reversed champagne. It can appear on any base coat and lays beneath most markings. It can have a gradient and should be somewhat subtle against the coat (e.g. it won't appear black on a palomino horse). When seen on a champagne horse, both types of sheen can show on the coat. Parts of the body can have a light sheen and other parts can have a dark sheen.

The geno code for Tarnish is written as:
nTn or TnTn