'Dust' in the Bible

Then the Lord said to Moses, “Say to Aaron, ‘Stretch out your staff and strike the dust of the earth, that it may become gnats through all the land of Egypt.’”

They did so; and Aaron stretched out his hand with his staff, and struck the dust of the earth, and there were gnats on man and beast. All the dust of the earth became gnats through all the land of Egypt.

It will become fine dust over all the land of Egypt, and will become boils breaking out with sores on man and beast through all the land of Egypt.”