Solomon's Diamond
Solomon’s Diamond was a large jewel originally belonging to the Kovari tribe. It was stolen from the Koravi temple sometime around the First Boer War (1880-1881); its whereabouts for the next century are undocumented. When Catherine Maxwell found it at Boothby's auction house she purchased it and returned to Buranda to restore it to its proper owners.
Physically, Solomon's Diamond was a huge jewel, almost the size of a person's head. Despite the name, it was not a diamond at all, but a large piece of quartz in a brilliant cut shape. (It had no connection to the biblical King Solomon.) Its attraction for others was the rumor that it was the Philosopher's Stone, able to transmute other substances into gold.
It was this legend that led to it being stolen by The Skull and his minions. It was never seen to create gold, but when Professor Morag began doing mad science experiments something happened and the entire temple exploded. Solomon's Diamond has not been seen since. (COMIC: The Danger, The Diamond, and the Dowager, etc.)