Steel blue
From Tardis Wiki, the free Doctor Who reference
Steel blue is a shade of blue color that resembles blue steel, i.e., steel which has been subjected to bluing for protection from rust. Josie Day wears a double-breasted steel blue tailcoat without sleeves. (COMIC: A Matter of Life and Death, The Lost Dimension) Rose Tyler wore a cropped jacket of steel blue leather. (TV: The Idiot's Lantern)