an old metallic key

Covered in cobwebs, this key seems to be very old indeed. The metal of the key has a blue hue to it, possibly made from the same stone of the Blue Mountains.

It is an old metallic key.
It weighs half a pound.

You identify an old metallic key.
It is an unsellable key.
It weighs eleven ounces, and it is worth about fifty busc.
Its keywords are key, old, metal, and metallic.