Perhaps someone should ask the Viatnamese if napalm caused similar effects to some of their stone buildings!
I think that the problem lies in concentrating the heat, even in modern pottery kilns it doesn't melt the clay only the glaze which has a lower melting point. I'm sure we have all seen the "reconstructions" on tv where they try to make Bronze/Iron Age tools, the heat required is considerable yet I haven't seen much vitrification of the oven interior.
I once used salvaged bricks from a demolished brickworks oven, they were well baked! but showed little sign of a glassy finish. I think that "vitrified" brick has an extra finish applied to the exterior.
Are there any sites down south showing this? Does it depend on rock type? So many questions-so few answers.
Love it! :-)
