I've read that one should NEVER ring a fire with rocks because the rocks may have absorbed moisture and might explode.

Other places I've read that one should ALWAYS ring a fire with rocks, to help keep the fire from spreading in an unwanted manner.

From the members here, which advice is correct?

Just remember your basic geology. Igneous stones simply cannot absorb moisture like a friable sedimetnary or metamorphic rock. Gather stones away from water sources and give a visual inspection for cracks. A fire ring is not a surefire barrier to spreading fire. If you ignite subsurface roots the embers can travel literally for months before igniting in a surface fire. A fire ring merely acts to physically corral your fuel. Your best option is to invest in a fireblanket to lay the fuel on. This also keeps the soil from being sterilised by heat. Fire rings should be dismantled and the blackened surfaces turned inward, unless the campground is well established with repeat use by others.

I read that that might happen. I've camped in lots of campsites with rings of rocks. Some sites require it. I've never had one explode.

I _have_ had chestnuts blow up, thought. Wow! Roasting chestnuts on an open fire can be a blast if you don't know how. Just remember, it's all fun and games till someone gets their eye put out. Then it's just a game.

It depends on the size of your fire. A small cooking fire works best ringed becase you can use the rocks to rest coffee pot, etc. on and keep them warm. A ringed fire also seems to build up a really hot bed of coals faster than an unringed one.

For a large fire to generate heat through the night, a ring is impractical, especially if you are burning long branches or logs and keep pushing them into the fire as their ends burn off.

Chris is right about sedimentary rocks. Choose igneous and watch out for deep cracks. Having said that, I have never seen a rock explode, but I've seen lots crack in half.

Unless camped in a van down by the river, as Chris Farley used to say, I would say use rocks if available. I think the exploding rock myth is just that. Hiss and crack maybe, but explode?

Hey, someone needs to send this into myth busters!!!

I have always heard, and been taught, that one should not use rocks from a creek to ring or heat in a fire. The moisture inside heats up, expands, and the rock explodes.

To me, exploding rocks sound kind of cool. So a couple of years ago I decided to try it. Rocks from the bottom of a deep creek, into a very hot fire burning with hickory and oak. Then I hid behind a very big Pine, and waited, and waited. No explosion, no cracks, maybe a little hiss. Repeated the same experiment, same results. Maybe it did happen sometime, somewhere, but I have never seen it, or talked to anyone who has.

i have personally seen rocks explode forcefully in a fire, but they were smallish acorn-sized ones taken right out of a stream and placed right in the middle of the fire. even at such a small size it was awfully dangerous (but perhaps smaller ones are a much greater risk than big ones that can't fly too far). i would expect that a lot of heat would be needed to make a big one blow up--since it's much more difficult to heat the entire thing rapidly, cracking is more likely than exploding. nevertheless, it definitely is possible for rocks to explode and shoot hot shards everywhere from a fire.

Alot depends on the type of rock and how you heat it.
Glass can explode if you heat it to quick for the heat to disipate evenly. The thicker the glass is the more dangerous.
Try freezing a thickly made glass and then pore boiling water over it and it will crack quickly because it expands faster than the heat can disipate. (take precautions)
Locally I would have no problem with using the limestone for a fire. Its like a sponge, and you could soak it over night and then use it and it will only fizzle. You can weld or oxy cut on it with no problems.
Local flint is completely different. Some of the local teenagers head to the beach and make fires though the summer months, and they usually pick up the flint rocks laying about. Every few years you hear a story about one exploding. Flint lets go with razor sharp shards. After hitting some with a hammer, I have had to pull some out imbedded in my skin.
Some rocks form with liquid and air in them. Not far from here is a place called Morala, and they pull Smokey Quartz geodes out of the Rhyolite. Some of the crytals have liquid bubbles, and I have been told that they can fly apart with some force too.

I'm pretty sure I read somewhere (probably either Mors Kochanski's 'Bushcraft' or maybe Cody Lundin's '98.6 degrees') that fire rings are unnecessary, destructive to the environment, and actually increase the risk of a forest fire. A ring of stones may trap the heat in between two stones and cause a fire to emerge days later; several forest fires have supposedly been traced to this. (Of course, if you're conscientious and scatter the rocks after you're finished, this is probably less of a concern.)

I've always thought that fire rings were to put your cookware on, and to keep klutzy people from walking into the fire while looking at something else.

Sue