Knowing my interest in primitive archery, my boss brought this in for me to see.  It is a point his mother found near the Flint River in Michigan.  Admittedly, I know little about stone points.  It appears to be from chert, from what little I know.  It was found eighty-two years ago.  Surprisingly, it is still relatively sharp.  The "blemish" appears to be a quartz deposit in the stone.  Almost looks metallic.  Without a magnifying glass, it's tough to tell.  Hope ya'll enjoy...