Stone Technology

STONE TECHNOLOGY

"Most of the material evidence for human behavior for the bulk of our time on earth - amounts to pieces of worked stone."

Harold Dibble

Demonstrating Stone Tool Manufacture at Flint Ridge, May 1996

Flint Ridge Knap-in - Mason's Campground - Brownsville, Ohio

Heat Treating Chert

Heat treating chert is a technique used to render lithic material easier to work and in some cases more colorful. Today’s approach to heat altering lithics is by using a pottery kiln. According to other knappers, this is the way to go, but I haven’t seen many aboriginal pottery kilns from the Archaic Period. The following experimental system may have been utilized by prehistoric peoples to alter the properties of their lithic materials.

Materials Needed

1. A lens shaped earthen pit
2. Quartz sand
3. 60lb of charcoal briquettes and/ or wood kindling
4. Chert blanks - do not use huge chunky pieces!
5. Digging implement

First, dig a lens shape into the ground about a foot deep. Soil condition is a concern. A fine dry soil is the best vs. mud being the worst as it tends to absorb too much of the heat. Now, line the inside of the pit with about 4-6 inches of quartz sand making sure the lens is even and gradual. Place the chert blanks, preforms or bifaces on the sand. Put them close together but not overlapping. Concentrate them in the middle - not at one end. Place another 2 inches of sand on the chert. Pack it down! Get in your pit and stamp the sand down. Insert a stick to verify the chert in the middle is 1* - 2 inches below the surface. The ends can be 1* inches or so. Then place 60lb of charcoal briquettes or other wood fuel on top of the sand, spreading them out evenly. Do not use - Matchlight charcoal. Use the type that requires lighter fluid. Light the fuel source and make sure it is burning. Do not disturb or uncover the blanks until the sand is cool enough to touch.

The bigger the load the better. If you have a lot of breakage, the chert needs to be deeper.

I hope the following photos will help demonstrate this experimental system.