Thanks to Pandora from alt.anthropology.paleo for sharing this paper:
Selection and Use of Manganese Dioxide by Neanderthals
Several Mousterian sites in France have yielded large numbers of small
black blocs. The usual interpretation is that these ‘manganese oxides’
were collected for their colouring properties and used in body
decoration, potentially for symbolic expression. Neanderthals
habitually used fire and if they needed black material for decoration,
soot and charcoal were readily available, whereas obtaining manganese
oxides would have incurred considerably higher costs. Compositional
analyses lead us to infer that late Neanderthals at Pech-de-l’Azé I
were deliberately selecting manganese dioxide. Combustion experiments
and thermo-gravimetric measurements demonstrate that manganese dioxide
reduces wood’s auto-ignition temperature and substantially increases
the rate of char combustion, leading us to conclude that the most
beneficial use for manganese dioxide was in fire-making. With
archaeological evidence for fire places and the conversion of the
manganese dioxide to powder, we argue that Neanderthals at
Pech-de-l’Azé I used manganese dioxide in fire-making and produced
fire on demand.
Article in Nature
I have often thought that if a Neanderthal travelled forward in time and found himself in 2016, he would think us extremely primitive.
"What? You need things to condition the air? Why not just tell your body what temperature you'd like?
You mean you spend all your time doing something you hate so that you can eat and have shelter? Why not just chase down a deer and sling it over your shoulder?
Why do you need all of this crude metal to do things that you can do with arm and brain power?
Wait...you're spending how much to reach Mars? Want me to show you how to do some astral projection? It's cheaper, really, and quite simple..."