Message was edited by: Luanne
It isnt a tooth but as Rhys says, it is stuffed with fossil corals. those ones are possibly from a genus known as Lithostrotion.
where did you find it? we might be able to tell more if we know that, such as possible age etc
The close up photos show coral fossils exposed on the surface of the stone.
The coral can be sectioned at different angles, so the circles are where the coral "cup" (where the tentacled polyp lived) has been cut straight across. The long markings with bands of lines are where the coral cup has been cup downwards.
They are the same thing cut across at differetn angles, which is one of the confusing things about fossils!