I don't how your stuff is, but the chert here in the KS flinthills is a bluish gray when I dig it out. But if I pick it up off the hillside it is a tan to brown color. I don't know if thats from thousands of years in the sun or prairie fires, but if its Brown it really works nice. I been meaning to ask you iowabow, over there along 34 before you cross the bridge to Illinois there is a rock cut along the road with some white seems in the strata. Is that good chert or is it chalk? Josh