A metallic layer material includes at least two metal sheets. Each sheet has a thickness of less than 1.5 mm. Between the sheets, a plastic layer is disposed, which is bonded to the metal sheets. The plastic layer comprises a plastic material and basalt fibers, and the basalt fibers have a modulus of elasticity exceeding 50 GPa. The basalt fibers may constitute 35-75% of the volume of the plastic layer. and may be comprised of 35-55 weight % of SiO.sub.2, 10-25 weight % of Al.sub.2O.sub.3, and 3-10 weight % of MgO. In aerospace applications and other applications requiring good specific strength, stiffness and damage tolerance, the metal sheets may be made of a metal having a tensile strength exceeding 0.20 GPa.