translation.en: On the lower left there is a picture of mother of pearl forming out of seawater. It's a layered structure that's mineral and then polymer, and it makes it very, very tough.
translation.zh: 左下方是珠母贝的照片。 它在海水中成形，是一个矿物质 和聚合物相间的层状结构 所以非常非常坚硬