Cave art

Visit Lascaux cave

http://www.lascaux.culture.fr/?lng=en#/fr/00.xml

Powder Rocks one art medium used for cave art drawings

This is a powder rock or paint rock. I'm sure some geologist or rock hound could give me the correct term. It's probably some sort of sandstone form. You break them open and beautiful powder or sand is inside. Most of the time it is red or purple. Sometimes, you'll find orange or even blue. The one at bottom right actually had two colors in the same rock. The outer layer was dark purple, the inner layer was tan.