Translation of "Pedernal" in English

Endurecí mi rostro como un pedernal porque sé que no quedaré defraudado.

I set my face like a flint because I know I shall not be put to shame.

Tomó entonces Seforá un pedernal, cortó el prepucio de su hijo y tocó las partes de Moisés, diciendo: "Eres mi esposo de sangre."

Immediately Sephora took a very sharp stone, and circumcised the foreskin of her son, and touched his feet, and said: A bloody spouse art thou to me.