CI 77492, also known as Hydrated Ferric Oxide, is a yellowish pigment derived from minerals that we use to add colour to our bar soaps.

‘CI’ stands for Colour Index and is used under the INCI (International Nomenclature of Cosmetic Ingredients) system to identify different colourants and pigments used in cosmetics and personal care products.

This ingredient is in a group of colourants known as Iron Oxides, which are compounds of iron and oxygen. Iron oxides include CI 77491 (red), CI 77492 (yellow) and CI 77499 (black) as the base colours, which are produced through different applications of heat in processes known as thermal decomposition, precipitation and calcination. Although these iron oxides can be found in nature, they can contain impurities such as manganese or other organic material, which is why the synthetically-produced versions are considered safer for use in personal care products. These compounds have a long history of use as colourants in cosmetics, and are considered safe for use by the FDA.

Other names: FeO₂H·nH₂O, Iron Hydroxide Oxide, Iron Oxides, Pigment Brown 6, Pigment Brown 7, Pigment Yellow 42, Pigment Yellow 43

REFERENCES

CFR - Code of Federal Regulations Title 21, Part 73 -- Listing Of Color Additives Exempt From Certification, Subpart C--Cosmetics. Iron Oxides. 21CFR73.2250