'Earthen' in the Bible

Thus saith Jehovah: Go and buy a potter's earthen flagon, and take of the elders of the people, and of the elders of the priests;

Thus saith Jehovah of hosts, the God of Israel: Take these writings, this writing of the purchase, both that which is sealed and this writing which is open; and put them in an earthen vessel, that they may remain many days.