Black Amazon of Mars (SF Classic)

Eric John Stark, a hero from Mercury, is taking his friend Camar to his birthplace, Kushat, in the north of Mars to die. Unfortunately Camar dies before they can get there from a bullet wound he received that he took for Stark. He gives Stark a talisman to take to the City of Kushat beyond which lies the Gates of Death. This is not just any talisman as Stark soon discovers there is a power from this ornament that was created to save the people of Mars from extinction.