The cypress casket was lowered into a larger solid zinc (traditionally lead) casket, which was soldered shut. This coffin was adorned with three bronze plaques: a simple cross at the head of the coffin, a plaque with the Pope's name and dates of birth and death at the centre, and Pope John Paul II's personal coat of arms at the foot. The zinc casket was finally lowered into a larger walnut (traditionally elm) casket, bearing three identical plaques, which was shut with nails of pure gold.
Looks like, once again, you posted a false statement on this site.
For some reason, I'm not surprised.