The strata around Aohama Coast in Moji-ku of Kitakyushu City have been known to yield baikaseki (apricot blossom stones) since ancient times. They have beautiful patterns that resemble strewn apricot blossoms. Instead of apricot blossoms, they are actually pieces of crinoid fossils that flourished in the warm seas 350 million years ago. A major production site and a particular apricot blossom stone have been designated as natural monuments of Fukuoka Prefecture.