Provided is a method for the production of a mineral substrate with a surface modified by organic groups. The method comprises placing the surface of a mineral substrate with silanol functional groups in contact with a solution of an organotrihydrosilane in an organic solvent at a temperature of less than 30.degree. C. The mineral substrate with silanol functions can comprise silica particles, a sheet of glass, quartz or mica as well as silicon of the wafer type covered by a layer of silica deposited by an appropriate preliminary treatment.