Stone tool, or natural weathering?

Today I was bored and I took some photos of this little box full of rocks here where I'm staying. I'm not sure why they have this little collection, but they do. I'm curious about this little red rock which seems to be chipped into a rough triangular prism shape. Is it a "core" left after someone has chipped blades off it, or do these sorts of rocks naturally weather into this shape?















I only noticed this tonight after the pics were uploaded, I might try to get some clearer pics tomorrow.

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