Thematic Bible: Natural rocks sometimes used as

So Gideon went into his house and prepared a kid, and unleavened cakes from an ephah of flour; the meat he put in a basket, and the broth he put in a pot, and brought them to him under the oak and presented them. And the angel of God said to him, "Take the meat and the unleavened cakes, and put them on this rock, and pour the broth over them." And he did so. Then the angel of the LORD reached out the tip of the staff that was in his hand, and touched the meat and the unleavened cakes; and there sprang up fire from the rock and consumed the flesh and the unleavened cakes; and the angel of the LORD vanished from his sight.

So Mano'ah took the kid with the cereal offering, and offered it upon the rock to the LORD, to him who works wonders. And when the flame went up toward heaven from the altar, the angel of the LORD ascended in the flame of the altar while Mano'ah and his wife looked on; and they fell on their faces to the ground.