[ars]

Specify bending strength, the chalk must not snap under specified force. Next define a writing pressure, angle and stroke speed and require fewer than x blank areas in the line. Require that the line width be within a specific tolerance, not too thick not too thin.

Maybe a spec like this doesn't exist now, but you could use the good chalk and write the spec based on how it did.

[fnordfnordfnord]

The trouble is that the places that sell chalk to universities don't rate chalk like this. Like I said in another post ITT, we derped around for a couple years before we just gave up and installed the damn whiteboards.