'Flint' in the Bible

Who led thee through that great and terrible wilderness, wherein were fiery serpents, and scorpions, and drought, where there was no water; who brought thee forth water out of the rock of flint;

Which turned the rock into a standing water, the flint into a fountain of waters.

Whose arrows are sharp, and all their bows bent, their horses' hoofs shall be counted like flint, and their wheels like a whirlwind:

For the Lord GOD 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 their looks, though they be a rebellious house.