At the Cueva (Cave) Anton, the scientists unearthed a pierced king scallop shell painted with orange pigment made of yellow goethite and red hematite collected some five kilometers from that site.
The researchers also discovered two pierced dog-cockleshells painted with traces of red hematite pigment.
The intervening layers, however, contain predominantly black basalt and red hematite
Microscopy reveals a complex microstratigraphy where multiple layers of red hematite
, yellow limonite and an unidentified white mineral lie over the uncoloured parent sandstone; they are divided by calcium oxalate layers and have an outer layer of oxalate which obscures the brilliant colours of the underlying minerals.
Rather it was more likely due to a metal oxide system as that of iron, possibly including other spinels such as hercynite, in which the changes between the various coloring agents (for example, red hematite
contrasted with black magnetite, or maghemite, or wustite, or some combination thereof) are reversible.