Inorganic pigments technically belong to the iron oxide group of pigments. This is because they are created by adding iron oxide to more elements. They are called inorganic as they are synthetically produced from metals including, titanium oxide, manganese violet, ultramarines, but also the mineral kaolinite AKA china clay.
The purpose of adding iron oxides is to provide solid colour and opacity, as well as widen the shade range. Titanium dioxide often produces lighter shades, while iron oxides produce darker shades. This makes inorganic pigments very versatile in colour range.
Pros of Inorganic Pigments: These are a non-toxic pigment and are not affected by light as well as being insoluble. This is beneficial in preventing pigment migration and discolouration. Inorganic pigments are least likely to cause an allergic reaction and therefore deemed a safer option of pigment.
Cons of Inorganic Pigments: Colour purity if often duller than that of organic pigments.