'Unhewn' in the Bible

Thou shalt build the altar of Jehovah thy God of unhewn stones; and thou shalt offer burnt-offerings thereon unto Jehovah thy God:

as Moses the servant of Jehovah commanded the children of Israel, as it is written in the book of the law of Moses, an altar of unhewn stones, upon which no man had lifted up any iron: and they offered thereon burnt-offerings unto Jehovah, and sacrificed peace-offerings.