iamond Head is Hawaii's most famous landmark. Known in Hawaiian as Le'ahi, so named by Hi'laka, the sister of the fire god Pele, because the summit supposedly resembles the forehead (lae) of the yellowfin tuna fish ('ahi). It wasn't until the late 1700's, when western traders thought they had found diamonds on the slope of the crater, that they began to call it Diamond Head. But before you head to the Diamond Head State Monument to dig for diamonds, you should know that (to the disappointment of the western explorers and traders) the so-called diamonds were merely calcite crystals, worthless to mine.