A magnetizable chemical composition including at least one polar solvent (4) selected from the group comprising an alcohol with a number of carbon atoms from C8 to C14, polytetrahydrofuran, or a mixture thereof; a ferromagnetic component, including a plurality of magnetizable particles (1) of Stable Single Domain (SSD) type selected from the group comprising magnetite, substituted magnetite and/or ferrite in an amount from 5 to 15% by volume of solvent and having a diameter from about 20 nm to 50 nm; and a polymer component (2) including polyvinyl butyral (PVB) or polyvinyl butyral-vinyl alcohol-vinyl acetate copolymer in a percentage from 3 to 15% by volume of solvent, the polymeric component being shaped as a net or mesh and delimiting a plurality of housing cells or zones (3), in each of which one of said particles (1) is housed immersed in the polar solvent (4). A method of obtaining such a composition, a microcapsule comprising the composition, an ink comprising the microcapsules and a method of testing a product marked with such ink.