When science meets primitive you realize that primitive might be simple but it also does it's job . Can hardly wait to see the results.
I know how you feel but very concerned about the fast rate of climb in the beginning. Even if it is cracked we will learn a lot from this.
First the color will be interesting to see
Second the texture will still be able to be analyzed
Not to mention what we learned about how the fire functions by producing charcoal and ash this combined with the sand created a perfect atmosphere that brought the chert to our target temp of 600 or very near it.