Gels having viscoelastic qualities, physical stability and adhesive properties, well suited for a wide variety of end applications, are prepared by crosslinking, by hydrosilylation, silicone compositions which contain: a polyorganosiloxanes POS (I) of SiH type; a polyorganosiloxanes POS (II) of SiVi type (Vi=vinyl); a polyorganosiloxanes POS (III) of monofunctional SiVi type; a platinum-based catalyst (D); and optionally, a polyorganosiloxanes POS (IV) of polydimethylsiloxane type.