Case XX Knives - Case Desk Knife Stainless Wharncliffe Blade with Full Tang. Model: CA11063. Brown Leather Sheath. EX17-3 pattern. 6 1/8" overall. 2 1/2" stainless wharncliffe blade. Full tang. Brown leather sheath. Black velvet gift box. Serialized. Limited edition of 500. Black Aztec stone is said to symbolize the dark skies of a solar eclipse, its bright streaks of Chalcopyrite make the fiery light that shines from behind the Mexican sun. The knives' lustrous black lip pearl accents border an intricate checkerboard of Blood Lightning and more Black Aztec.