'Flint' in the Bible

who led thee through the great and terrible wilderness, a wilderness of fiery serpents, and scorpions, and drought, where there is no water; who brought thee forth water out of the rock of flint;

Who turned the rock into a pool of water, the flint into a fountain of waters.

their arrows are sharp, and all their bows bent; their horses' hoofs are reckoned as the flint, and their wheels as a whirlwind.

But the Lord Jehovah will help me: therefore shall I not be confounded; therefore have I set my face like a flint, and I know that I shall not be ashamed.

As an adamant harder than flint have I made thy forehead. Fear them not, neither be dismayed at them, for they are a rebellious house.