This is a tough one because of the lighting. Could be American Blue or Mink. Can you get an outside picture of her, shooting down? It's usually the best way to get their true color. Also, make sure your camera isn't too close that the flash washes her out.
The spot above her tail is rusting, it's normal in rats. Diet can cause it, also the exposure to too much light and with Minks, it's just happens. They are rusty and have odd molting patterns throughout their lives. lol
That said, she LOOKS American Blue.![]()