A mineral used in electronics, automotive and even in cosmetics to add sparkle to makeup is being mined in Madagascar by an underground army of child laborers, NBC News reports.

Mica is mined by hand in a cluster of sites in Madagascar, an island nation of 25.5 million people located off the southeast coast of Africa.

NBC News traveled more than 400 miles through Madagascar’s remote south with the Dutch child protection group Terre des Hommes and witnessed scores of children working in unregulated and poorly-ventilated mica pits, as well as processing centers, alongside other family members.

Interviews with executives in Madagascar’s mica industry showed that the prevalence of child labor is well known but largely dismissed as a byproduct of extreme poverty. Children as young as 4 years old perform long hours of labor-intensive work in often dangerous conditions to collect a mineral whose price will be inflated nearly 500 times by the time it leaves Madagascar’s shores on route to China, where more than 91% was shipped in 2018.