New research suggests that, 60,000 years ago, cave-dwelling Neanderthals figured out how to use the chemical properties of manganese dioxide to start wood fires. The study, published in Scientific Reports, disputes earlier research indicating that these humanoids gathered chunks of black manganese ore only to use the ore as a pigment in makeup or paint.

Here’s why archeologists changed their minds: Many chunks of black ore have been found at Neanderthal sites in France, and most of these are made up predominantly of manganese dioxide, a chemical that is currently a key ingredient in alkaline batteries. Some of the samples show scratch marks, as if the ore had been ground away into a powder. However, if the cave-dwellers needed a black pigment, they would need to look no further than the charcoal from the fire. It doesn’t make much sense that they would have expended valuable resources gathering this particular type of rock. Furthermore, the sites where they likely sourced the ore were also abundant in other types of soft, black rocks that would have served equally well as a pigment. The fact that the Neanderthals were selecting the manganese dioxide over the others suggests that it was being used for a purpose related to some other unique property.

Abrasion marks on the chunks of ore suggest they were ground by stone into powder.

While the researchers found no direct evidence that the manganese dioxide was being used as a fire starter, they did discover this: the manganese dioxide ore, when powdered and added to wood chips, significantly lowered the temperature required to cause the wood to combust. In experiments, the powder produced from the ores found on site worked better as a fire starter than even pure commercial-grade magnesium dioxide. None of the other soft black ores available in the area share this property.

How Neanderthals figured this out is anyone’s guess, although maybe we shouldn’t be all that surprised. It is possible that an initial artistic intent gave way to a more practical use.

Hundreds of thousands of years of daily experimentation would yield some pretty amazing discoveries. And in this instance that appears to be the case, as these ancient chemists unlocked the secret to spark a pretty sweet and totally useful reaction.