Tumbling Flint-knapped Laser Filter Glass

Connection of between tumbling glass, laser fusion and Star Trek. Since I don't have a water cooled grinder I knapped some shapes and tumbled them in my new rock tumbler. The glass has a unique history as a laser filter and in this case for the National Ignition Facility (NIF). The large glass blocks do eventually crack but NIF does not part with the material, I asked. I suspect the material that lands in the hands of rock hounds is rejected plates from the manufacturer.