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In The Hobbit and The Lord of the Rings, we are introduced to Mithril, a metal described as being stronger than steel but much lighter in weight. It is also shown to have a silver sheen and the crafting of it is implied to require greater skill than steel.
Tolkien's works are often written in such a way as to create a real world mythological connection; Middle Earth is just our world in the distant past.
In modern times, aluminum and its alloys are used for many industrial purposes due to its light weight -- at 35 to 45% less weight than steel, when built to the same standards, it is considered much stronger per unit weight. It also has a nice silverish gleam when polished and was in use for over a century by the time of Tolkien's writings.
So, to the point: is there any counter proof to the theory that mithril may be the substance currently known as aluminum? I do not require a Word of God answer, but if there is one that would be great.