Some waxes are of mineral origin.
They are formed mainly by fatty acid esters but contain also free fatty acids and resins. Montan wax is the best known and originates from mob or lignite, this fossilized compound representing a late step of the transformation of vegetals into hydrocarbons. Wax esters are saponified by hot alkaline solutions and give a fatty acid and an alcohol. They are soluble in aromatic solvents, chloroform, ethers, esters and ketones. R1 et R2 have commonly 10 to 20 carbon atoms or more.