Lucky strike: testing the utility of manganese dioxide powder in Neandertal percussive fire making

Late Middle Palaeolithic Neandertals in France are known to have engaged in the collection and grinding of black minerals rich in manganese dioxide (MnO₂), generally presumed for symbolic use as powdered pigments. However, lab-based experiments conducted by Heyes and colleagues (Sci Rep 6: 22159, 2016) have shown that the addition of powdered MnO₂ to wood turnings both reduces the temperature required for combustion by ca. 80–180 °C and significantly increases the rate of combustion. This special pyrotechnic property of powdered MnO₂ may have been observed and leveraged by Neandertals to aid in fire making—a technology known to Neandertals in this region by at least 50,000 years ago. To test this idea, a series of actualistic fire-making experiments were performed to determine the practical applicability of MnO₂ as a tinder-enhancing additive. The flint-and-pyrite percussive fire-making method was employed to produce sparks that were directed onto eight different types of tinder common to temperate Northwest Europe to determine if and to what degree the addition of MnO₂ powder improved their ability to capture sparks that then propagate into glowing embers. The results show that MnO₂ does indeed considerably improve the ignition efficiency of tinder material over untreated tinder, both in terms of the point of first ignition and the total number of ignitions achieved. It was observed, however, that the incidental addition of pyrite dust onto a tinder over the course of an experiment also appeared to improve its ability to capture sparks. Supplemental experiments using tinder pre-mixed with powdered pyrite confirmed this hypothesis, suggesting pyrite powder similarly expedites fire production. While this finding may raise questions regarding the need for collecting MnO₂ for this purpose, its potential utility may lie in (1) its relative softness compared to pyrite, making it much easier to grind or scrape into powder, and (2) the greater potential for MnO₂-bearing deposits to yield larger quantities of usable raw material compared to pyrite-bearing outcrops, making it relatively more abundant in some areas. Thus, when available, it is clear that adding MnO₂ to tinder would have noticeably reduced the time and energy required to produce fire, making it a potentially novel Neandertal innovation complementary to the fire-making process.