'Flint' in the Bible

But Zipporah took a flint knife, cut off the foreskin of her son and touched it to Moses' feet, and said, "Surely you are a bridegroom of blood to me."

and who brought you through the great, fearful desert of venomous serpents and scorpions, an arid place with no water. He made water flow from a flint rock and

At that time the Lord told Joshua, "Make flint knives and circumcise the Israelites once again."

So Joshua made flint knives and circumcised the Israelites on the Hill of the Foreskins.

Their arrows are sharpened, and all their bows are prepared. The hooves of their horses are hard as flint, and their chariot wheels are like a windstorm.

I have made your forehead harder than flint -- like diamond! Do not fear them or be terrified of the looks they give you, for they are a rebellious house."