a twisted iron key

According to the small, flat dents and sharp corners in the blade, the key seems to be hammered and filed from a single piece of iron. The key has a strange twist at the end of the shaft, which leaves the blade upside down compared to the handle.

It is a twisted iron key.
It weighs half a pound.

You identify a twisted iron key.
It is an unsellable key.
It weighs seven ounces, and it is worth about five celeb.
Its keywords are key, twisted, and iron.