I Am Taken From A Mine, And Shut Up In A Wooden Case

Riddle: I am taken from a mine, and shut up in a wooden case, from which I am never released, and yet I am used by almost everybody. What am I?

Answer: Pencil lead.

Source: https://www.riddles.com/323

I am taken from a mine, and shut up in a wooden case, from which I am never released, and yet I am used by almost everybody. What am I? — I am taken from a mine, and shut up in a wooden case by Anonymous v1.

Riddle: I am taken from a mine, and shut up in a wooden case, from which I am never released, and yet I am used by almost everybody. What am I? Answer: Pencil lead. — by Anonymous v2.