Many things can create one, it can be of any shape or size, it is created for various reasons, and it can shrink or grow with time.
A metal neither black nor red,
as heavy as man's golden greed.
What you do to stay ahead,
with friend or foe or arrow and steed.
Select a pack of riddles and try to solve it in an interesting way.
This riddle appears in the following downloadable PDF files: