The Bronze of Eddarta

Raiders of the sacred stone - Somewhere in Eddarta, stolen by a treacherous assassin, lay the Ra'ira, the most precious jewel of the burning desert world of Gandalara. Armed with the steel sword Serkajon, Rikardon and his telepathic warcat Keeshah seek the sacred stone. With the aid of Tarani, a beautiful illusionist with a mysterious past, they make a daring raid on Eddarta's royal citadel - to rescue the gem before its awesome powers can be used for destruction. (from the back cover of the Bantam Books first edition)