The velvet gene can be expressed with any standard or mutation. It shows itself as a dark mask/veiling all the way down the top of the body. Sometimes it's hard to see in whites, and the only way you know they are tov, is by the offspring they produce. Some chins may also have paw stripes.
Some colors are simply labled TOV, like ebony tov, white tov, etc... other colors have been given different names. Black velvets are technically a standard tov, brown velvets are a beige tov. Does that make sense?