GeologyRocks

Oooh, Kryptonite! (No, that's a joke...)

It looks like a piece of badly abraded fluorite to me: http://en.wikipedia.org/wiki/Fluorite I may well be wrong though. If you have a UV light handy you could see if it fluoresces, but a negative result doesn't necessarily rule fluorite out. Other than that, there's the Mohs Scale hardness test, fluorite is 4.

Hope this helps,

Ben. 

Thanks a lot, I think that is definitely it.  Green is my favorite color and I think its really cool looking.

 So, does it mean that I can somehow make my rock look like this one I found online?  If so, how?

It's doubtful whether your example would be of gemstone quality, it's likely to have inclusions, variations in tone, and fractures running through it. But if it were the right quality you'd have to have it cut and polished. There are many many different configurations in the number of facets that could be cut, depending upon the shape of the original specimen and the desired shape that you wanted to end up with, etc.

makes sense to me.....how should I go about polishing it?  Do I need to get a rock tumbler?  or would I get the same effect by putting in a container with water and sand and throwing it in my dryer? Or is there a better method than either of the afformentioned?

Tumbler would get my vote. But you're more likely to end up with something that looks like this: 

Than the picture you posted earlier... 

It looks like itll end up like those.  I might just keep it as is.....maybe if i rub it enough over time itll polish itself.....thanks for the help, it is much appreciated.

Some fluorite is very friable so don't try to polish it too hard or you might end up with a small heap of fragments.

I concure...green flourite looks like what it is. Natives believed green flourite brang good fortune.