Yep..that's a rock. Some refer to it as a stone. We see a few of those in new england. Not so much this time of year though. Migratory you may ask..no no..just burried under snow and ice..keep the penny ;-)
Although the What-Is-It forum tends to be a more "serious-minded" place than other T-Net forums, it does have its jokester contingent... which is having some good-natured fun with your rock. I'll offer you a more scholarly-toned answer about it.
You asked for "thoughts," without specifying what you want to know. Are you enquiring about what it is made of, or, what it might have been used for?
Well-focused super-closeup photos are needed to identify the mineral(s) it is made of. In your current photos, it looks to me like Quartzite, which is a Metamorphic type of stone composed of pressure-compressed quartz sandstone.
As to what your rock might have been used for... it appears to have been shaped entirely by Mother Nature, not by man. Its corners have been worn smooth by natural forces. Parts of its surface are darker than others, which on some types of stone indicates some areas of its surface have been broken off more recently than the rest of its surface.
The following is based on my photo-based guess that your rock is Quartzite, which is a Metamorphic variety of stone:
You say it was found in Florida. The "native" rocks in that state are the Sedimentary kind (not Metamorphic, nor Igneous). So, your rock must have been transported to Florida by humans from an out-of-state location where Metamorphic rocks are the primary geological type.
Cannonballs got it....Google yourself images of Appalachian quartzite. Oh yah! remember the word quartzite when your in a game of Scrabble. I used it in a game once and it sure will rack up the points. I killed it in that game.
A fossilized loaf of bread .... Okay, where's my penny?
Seriously, I am having some trouble coming up with a realistic guess, without more information than provided. Is it metallic? Will a magnet stick to it? Does it look as if it may have been burned in spots? If so, is one side burned more so than the other? My eyesight is not so good and my bi-focals need a new prescription at the moment. Even the enlarged images do not help me much. It looks like it has a pinkish hue with darker splotches and may have a sandy crust. Is that right so far?