Exodus 20:24-25

24An altar of earth you shall make for me and sacrifice on it your burnt offerings and your peace offerings, your sheep and your oxen. aIn every place where I cause my name to be remembered I will come to you and bbless you. 25 cIf you make me an altar of stone, dyou shall not build it of hewn stones, for if you wield your tool on it you profane it.

Deuteronomy 27:5-6

5And there you shall build an altar to the Lord your God, an altar of stones. eYou shall wield no iron tool on them; 6you shall build an altar to the Lord your God of uncut
Hebrew whole
stones. And you shall offer burnt offerings on it to the Lord your God,

1 Kings 18:31-32

31Elijah took twelve stones, according to the number of the tribes of the sons of Jacob, to whom the word of the Lord came, saying, gIsrael shall be your name,” 32and with the stones he built an altar in the name of the Lord. And he made a trench about the altar, as great as would contain two seahs
A  seah was about 7 quarts or 7.3 liters
of seed.
Copyright information for ESV