Historical Australian antique iron grave marker

This is a closeup image of an antique rusty cast iron grave marker in a historical graveyard cementary in Kalbar, Queensland, Australia which was established in 1877. This graveyard and the grave markers as shown in this image are over 150 years old. It is made of heavy cast iron which is very rusty and has the appearance of a key head shape. It shows no name, just the number five 5.