I met a fella named Marvin at the House Mountain knap in. He's from West Virginia and knaps that Kanawha chert very well with copper. Pete Davis, who hosts the House Mountain knap in in Virginia does real well with the material using antler.
Here's one Marvin gave me:
This is what it looks like in spall form, making you wonder how anyone ever got the notion to try to knap it:
Here's one I banged out using antler direct and indirect percussion:
Oh, but here's what other side looks like!:
Keith