I call it a Hernando Point. Let me know if you disagree.
If he found it in a North Florida river it could be quartzite.Hard to tell the material from the pictures, at first I thought it was quartzite (which I don't think exist in Florida, well I didn't find any) but looks to be coral.
Putnam, Cypress Creek, or similar. Definitely not a Hernando. Unusual material, shows the NA's had a good trade network.