 In the first part of this module we're going to be talking about the physical and chemical properties of the minerals that make up ochre pigments. So as mentioned earlier these are mostly iron oxides and hydroxides with various degrees of oxidation of the iron that give it its various types of earth-toned colors ranging from yellows to browns to oranges to reds. And we'll find that the different oxidation states of iron yield different types of color, different qualities of color, and the matrix that the iron oxides are mixed with will determine the physical properties of the minerals. We'll also talk a bit about how these types of oxides and clay minerals are formed in nature and why it is really quite natural that these are some of the first pigments that came to be used by humans. The iron oxides and oxyhydroxides and clay minerals are all minerals that form at the surface of the earth through low-temperature weathering processes. So that means that they're going to be concentrated near water and in environments that are easily accessible near surface or at the surface of the earth. These are things that one may have simply stumbled upon, perhaps in the form of a powdered rock or perhaps in the form of simply a mud that could then be spread and used as a as a paint crude form of paint or makeup directly as is and slightly more lithified, which is a word that means turn to stone, a slightly more lithified version of these muds that could then be used as a sort of a crayon or pencil for drawing on other on other substances on other rocks and wood and such.