Nowadays there is an intense research for developing alternative thermal energies storage materials, able to work at the 800-1000 degrees C temperature range, for concentrated solar plants. The challenge is wide and extends from different ceramics to natural rocks. In the present work, the aim is first to select representative basaltic rocks from different localities over the Mediterranean basin and close volcanic sites, these going from Tenerife Island up to Egypt. Second, to evaluate the effect of mineralogy, composition and texture of such natural materials on thermal properties during heating process (up to.1000 degrees C). All analyzed basalts are stable over a wide range of temperatures and especially those containing high amounts of MgO and FeO*, since they preent valuable physical and chemical potential as being used as thermal storage material in concentrated solar plant operating until 1000 degrees C.