I have allways been fastinated by sharks and have searched for fossilized sharks teeth since I was a child...I am now 37 years old and about 2 years ago while looking for fossilized sharks teeth I fould a tooth, which I believe to be a great white shark tooth.  This tooth is not fossilized....I found it at a shell rock pit near my home in Florida.  The tooth is very light...and very very fragile...I can easily chip pieces of it away with my fingernail.  I have found many teeth at this site, including extinct mako, tiger, bull, and a lot of others I am not sure about. I allways thought it took several thousand of years for teeth to fossilize.  What would cause this perticular tooth to be in what I call the begining stage of fossilisation?

Hi Dwayne, I thought I'd have a go at answering your question since it's been here for a while now - I assumed one of our palaeontologists or taphonomists would have picked up on it, but they've all probably been on fieldwork for the summer.

Recent animal remains (by recent I mean from the last 140,000 years or so) are usually referred to a "sub-fossil" since they have not undergone much mineralisation. The bone (or tooth) loses it's protein component after a few years, which makes it much more brittle and flaky. In true fossils minerals have entered the spaces left by the protein and recrystalised, making a harder, denser substance than the original bone or tooth.

I hope this explains the phenomenon you have been seeing.