The Ten Commandments were written on stone, not in metal, clay, or mud which can be melted, shaped or molded. None of the commandments, like the tablets on which they were originally carved, is malleable. Each can be broken, but not altered.
“I give them eternal life, and they shall never perish; no one will snatch them out of my hand. My Father, who has given them to me, is greater than all; no one can snatch them out of my Father’s hand. I and the Father are one.””