The pipes were beginning to rust, discolouring the water.

It is, though, surprisingly inert. A lump of graphite or a diamond will sit happily on a laboratory bench without bursting into flames, or even rusting, and is impervious to the action of water.

Plastic rockery stone stability is mainly rely on the main structure completed, but with the passage of time, steel in the process of contact with air and water, prone to corrosion and rust.