The Jewel Mountains
The Jewel Mountains are a mountain range on Krypton composed of crystalline rock and gems. This panoramic geological feature is considered by some to be a tourist destination and the mountains are visited by Superman and Lyla Lerrol (S No. 141, Nov 1960: "Superman's Return to Krypton").
At least part of the Jewel Mountains are thought to have been formed by the accumulated carcasses of gigantic Crystal Birds that flew to the location deep in Krypton's past to perish at the end of their lives. It is from these Jewel Mountains that the raw material for Jewel Kryptonite may be obtained (Act No. 310/1, Mar 1964: "Secret of Kryptonite Six!").
The Jewel Mountains were discovered by explorer Bor-Ak (S No. 164/2, Oct 1963: "The Fugitive from the Phantom Zone").