'Earthen' in the Bible

Thus said Jehovah, 'Go, and thou hast got a potter's earthen vessel, and of the elders of the people, and of the elders of the priests,

'Thus said Jehovah of Hosts, God of Israel, Take these books, this purchase-book, both the sealed one and the open one, and thou hast put them in an earthen vessel, that they may remain many days;