From the Mid Archaic Period, some 6500BP, likely the Benton Culture as they were about the 'height' of the Mid Archaic--and the most prolific at making the three-quarter groove style of axe. The dense black stone is likely a dark quartzite that started as a large river cobble. The tip was anciently worked (salvaged after a bit break) so the present length is 5&9/16". Height is 2&9/16", and the thickest spot is 1&13/16" on the heel. There are some light bands of quartz in the stone, iron stained. A few light plow scratches indicate the piece was a field find. The best polish is on the flat 'top' of the axe--end-to-end they ground that flat face; good polish on the bit side that didn't get use-dinged, smooth polish on the place where part of the bit broke away (they hit something hard, VERY HARD)...makes my old shoulder ache to think of connecting with a surface hard enough to do this to a stone as hard as quartzite. Life was tough, a thirty-five year old was an old man. The piece is guaranteed authentic in every detail, shipping is $11 by Priority Mail, packed tight. I welcome checks or M.O.s but please note I do not use paypal--Roy A.