A new pozzolanic material basically conformed of microsilica with a minimum of silica of 85% in its composition is described, where the silica of the material is conformed mainly of cristobalite and tridimite. Unlike microsilica conformed basically of quartz, the microsilica of the invention exhibits greater pozzolanic indexes and provides improved characteristics of durability to concrete cements and in smaller proportions. Also simple and low consumption energy methods for obtaining the pozzolanic material of the invention are described.