Abstract: A qualification method which enables a fast, exact and numerical determination of puzzoulana-properties of solid materials and thus a short evaluation of said solid materials from the point of view of industrial usability.According to this method the puzzoulana-properties and activity of solid materials can be defined by a single figure as a result of their chemical and physical properties. The material to be analyzed is brought together with fluoride ions in an acidic medium in a system having constant heat capacity and the change of the heat quantity is measured and evaluated in the initial, suitable linear, phase of the resulting reaction. The time function of the change of the heat quantity of the system is converted into a change of voltage and the rise of this curve is determined advantageously in the linear section. Advantageously the change of the heat quantity of the system is measured within less than 30 seconds, favorably at about the 20th second.