A method of extracting active mineral liquid from a rock such as granite is described. This method comprises charging an extraction vessel with finely divided granite at ambient temperature and pressure; introducing an aqueous ammonia solution with agitating and then diluted sulfuric acid into the vessel; introducing 98% ethyl alcohol at below 80.degree. C. into the vessel to elevate the inner pressure of the vessel to 2-3 kg/cm.sup.2 for facilitating the formation of complexes; and agitating the resulting reaction mixture for 20-160 minutes at 80.degree. C. to 85.degree. C. while maintaining the internal pressure of the vessel. The active mineral liquid is advantageously used as a mineral source for soils, animals, plants, the human body and so forth, and as an agent for the purification of waterworks as well as for the treatment of wastewater.