How do you tell a rock from stone tool?

[Tybee]

I found an interesting rock yesterday filling in the giant hole my sheepdog dug (another thread, I guess) and I am wondering how you tell a rock from a stone tool?

To me it looks like a tool, and I found this Smithsonian video:

http://humanorigins.si.edu/multimedia/videos/how-tell-rock-stone-tool

Does anybody have any pointers, or good resources with this?

[razz]

When I was in Newfoundland. a particular shale was obviously the type used for cutting. This was confirmed by the museum staff at L'anse aux Meadows. Not sure about other stones though.

[Tybee]

Thanks, Razz.