dre mainly found in tropical oceans.10

When some sand gets inside the shell of an oyster, the oyster covers this area of its shell with layers of a mineral called mother-of- pearl.In 1894 CE, Kokichi Mikimoto, a Japanese businessman, discovered a way to make pearls.He put a small natural mother-of- pearl 'bead into a living oyster shell.The oyster began to cover the 'bead' with more layers of mother-of-pearl, and eventually the bead became a pearl.???????????????