THE MATERIAL SHOWN LOOKS LIKE A POOR CHOICE FOR STONE TOOL OR BLADE BUT SOMETIMES THEY NO DOUBT USED WHAT WAS AVAILABLE. THE MATERIAL REMINDS ME OF THE BRICK IT IS LAYING ON.
I HAVE SEEN TOOLS MADE OF BRICK, BROKEN POTTERY, GLASS,QUARTZ, SLATE, LIMESTONE AND VARIOUS IGNEOUS ROCKS. SLATE AND OTHER SEDIMENTARY ROCKS ARE USUALLY SHAPED BY GRINDING OR PECKING AS THEY DON'T FLAKE WELL.
PERHAPS SOME OF THE SOFTER ROCKS WERE USED FOR TEACHING TECKNIQUES TO BEGINNERS. NO DOUBT AN EXPERT FLINT KNAPPER PREFERRED GOOD MATERIAL BUT NOT EVERYONE WAS BLESSED WITH A GOOD SUPPLY OF OBSIDIAN OR FLINT SO THERE IS A WIDE VARIETY OF ODD ARTEFACTS OUT THERE. GOOD FLINT OR CHERT OR OBSIDIAN WAS WIDELY TRADED IN NORTH AND SOUTH AMERICA.
LOOK AROUND FOR A POINT SHOW (ARTEFACT SHOW) IN YOIUR AREA AND SOMEONE THERE SHOULD BE ABLE TO GIVE YOU SOME GOOD INFO ON IT. GOOD LUCK
