Abstract: A granular polymer composition having increased water absorption and desorption capability, resistance to photogradation and increased life span, comprising a water-insoluble but swellable cross-linked polymer material formed of at least one polymer and/or copolymer prepared from at least one unsaturated ethylene monomer having at least one carboxylic, amide, sulfuric, sulfonic, phosphoric, phosphonic, or hydroxyl functional group and at least one powdered mineral charge well dispersed in and intimately bonded to said polymer as a result of its introduction into the mixture of monomers of the same type or of a different type before their polymerization into said polymer or copolymer.