Colornts for early art: Goethite or Yellow Ochre (Yellow Pigment).
Goethite or Yellow Ochre (Yellow Pigment)
The second image (Catalan Museum of Archaeology - 21.jpg) features a yellowish, earthy stone. This is likely goethite or a form of yellow ochre.
Historical Use: Widely used across the Stone Age and in Ancient Greece to create shades of yellow and tan.
Characteristics: It is an iron oxide mineral that is quite common and easily ground into a stable pigment.
Exhibited at the Catalan Museum of Archaeology, Barcelona, Spain. Museu d'Arqueologia de Catalunya (MAC).