Taken From A Mine

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: I am pencil lead.

Source: https://www.riddles.com/729

RELATED RIDDLE

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: I am pencil lead. — 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: I am pencil lead. — by Anonymous v2.