John O wrote:
>> Could a guy, or a gal, use rocks in the pan instead?
>
> What is sand, but ground up rocks. :-) I think the idea is to provide a
> thermal mass, and seems like rocks would do the job. Given a typical pan,
> the smaller the rocks the more thermal mass you're going to get.
>

> I would be careful about rocks that might 'crack apart violently' when
> heated.
>
> John O

I just want to repeat your last line, John:
"I would be careful about rocks that might 'crack apart violently' when heated."

Don't ask me how I know this, but it has to do with a campfire and rocks around
the edge, and a much larger fire than the rock ring was intended for.

BOB