Is Oracle Bone Inscriptions written on tortoise shell or ivory?

Oracle Bone Inscriptions is the earliest and most complete ancient script discovered by China. Oracle Bone Inscriptions mainly refers to the Oracle Bone Inscriptions of Yin Ruins, also known as "Yin Ruins Characters" and "Yin Qi", written on the bones of tortoise shells and beasts in Shang Dynasty. /kloc-at the end of 0/9, it was discovered at the site of Yindu (now Xiaotun, Anyang, Henan). Oracle Bone Inscriptions inherited Wen Tao's word-making method, which was carved (or written) on tortoise shells and animal bones by the royal family in the late Shang Dynasty of China (14 ~1century) for divination. After the demise of Shang Dynasty and the rise of Zhou Dynasty, Oracle Bone Inscriptions continued to be used for some time.