>Production procedure. Stocks claims that the stone is inserted through
>the narrow neck and then laid flat.
That's what he describes for rocks like steatite (be it a schist or hornfels) and alabaster (uses just the borer to cut)...... those rocks are made of the minerals talc and gypsum, respectfully (do I have to explain to you why that is not a problem). In the hardrock experiments it is the quartz sand that the borer spins around in the hole that enlarges the it by grinding, not the borer itself. Borers of different sizes are needed......
>Page 150 of Stocks Book.
That one is made out of travertine (a marble like limestone)...... you can just about scratch with you fingernail, and a "constant" few mm thickness is a gross exaggeration of such (it's neither "constant" nor few in mm).
Archae Solenhofen (firstname.lastname@example.org)