I'm not sure where to ask this question, but I thought there might be people on this list who are familiar with rocks and minerals. I've been thinking about the first smelting of ore (which seems to have happened just twice in all of human history) and wondering how it happened. Possibly it was just an accident that someone built a campfire over a bit of lead ore and noticed the lead the next day, but how likely is that have happened twice? The alternative is that someone was experimenting with burning different rocks, and I'm wondering how likely that second possibility is. Are there enough rocks that would be interesting to burn that it would have seemed worthwhile to experiment?

Do any rocks explode at campfire temperatures? That might have been fun to play with if not actually useful. Coal might actually make a practical campfire (does it?) so someone might have been looking for other rocks to use as fuel. Sulfur would make a terrible campfire but might be interesting. I've been able to find references to shale tar and shale oil which supposedly burn, but can't find out if they burn in a campfire or need higher temperatures. Are there other rocks that would be useful or interesting to throw in a campfire that stone-age people might have known about? Basically, would they have found enough different rocks that are interesting to burn that it might have prompted experiments?

  • $\begingroup$ most porous rocks will explode at campfire temperatures if they have any water content. the water flashes to steam. that is why its important not to use them when making fire rings. $\endgroup$
    – John
    Nov 10, 2023 at 1:55
  • $\begingroup$ Interesting question, +1. But the line "which seems to have happened just twice in all of human histor" is strange? $\endgroup$ Nov 10, 2023 at 8:39
  • $\begingroup$ @JeopardyTempest, archeology suggests it happened once in Asia and once in South America. $\endgroup$ Nov 10, 2023 at 12:29
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    $\begingroup$ @DavidGudeman Or perhaps three times in Asia (Asia Minor, Southern Asia, and China), perhaps one or two times in Africa, and perhaps two times in the Americas. It certainly happened at least twice but to say it happened only twice is a bit over the top. $\endgroup$ Nov 11, 2023 at 10:07
  • $\begingroup$ @DavidHammen, my reading says different, but maybe I need to do a bit more research. If you're right, that is useful evidence for my question of whether neolithic people experimented with burning rocks. $\endgroup$ Nov 11, 2023 at 10:59

2 Answers 2


From what I was made aware of a long time ago, it appears your serendipitous camp fire hypothesis is thought to be plausible by some historians. The lack of written records makes it difficult to be certain.

Through serendipity and then further experimentation using the same type, or similar rocks, over time people acquired the knowledge of which rocks would yield what metals.

Occasionally, surprises were encountered, such as when what was thought to be copper mineralization gave a metal that was totally new, troublesome and initially of no use. The metal that was produced was called Nick's copper, or the Devil's copper, which later lead to the metal being called nickel.

Nickel was first isolated and classified as an element in 1751 by Axel Fredrik Cronstedt, who initially mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden. The element's name comes from a mischievous sprite of German miner mythology, Nickel (similar to Old Nick).


**greetings. This answer is predicated on the information I gleaned as the son of a Kennecott Copper Corp. engineer, and metallurgist.

It was said, then, (50+ years ago) that copper was mined by aboriginal people at least 6,000 years ago, according to anthropologists, primarily because"native copper" could be recognized by them in attractive deposits that required a minimal amount of smelting in order to provide a material for crafts etc.. (It was hypothesized that the related amount of lead and zinc likely contributed to non-OSHA approved air quality in the vicinity, but that's a different story.)


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