tell me a riddle

Sure, here's a riddle for you:

I am taken from a mine, and shut in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

i dont know

The answer to the riddle is "pencil lead." Pencil lead is made from graphite, which is mined from the earth. It is encased in a wooden pencil and is constantly used by people for writing or drawing, but it is never fully released from its wooden casing.