My blade was found in Lee co. It is a agate basin knife form, says (Bill Jackson) thin and has heavy grinding along the shoulders half way up the blade on both sides of the base, not sure about material but you can just bout read through it! Im no pro but that "very nice blade" you have there looks like the cache blades found up round Mnt. pleasant. theres folks here that could help more bout the age and such, the flakin looks old but Im not sure on the shape, (by "old" I mean paleo/trans/early arch. sweet blade and Iowa has always given nice blades IF your in the missippi valley region, This is another Iowa blade found just feet from where the agate was found its just shy of 5".