Abstract: The invention provides a process for the production of a high grade amorphous silica having a purity of at least 90% active silica of the formula SiO.sub.2.nH.sub.2 O, comprising the steps of:a. comminuting and wet classification of porcellanite rock to form granules having an average diameter of 200 microns to 8 mm;b. combining the resulting granules with NaOH at a temperature of up to 100.degree. C. to form a product containing sodium silicates;c. separating a liquid containing the sodium silicates from solid waste;d. adding CO.sub.2 to the liquid product to form SiO.sub.2.nH.sub.2 O and Na.sub.2 CO.sub.3 ;e. washing the resulting product to effect a separation of the precipitated SiO.sub.2.nH.sub.2 O from the soluble Na.sub.2 CO.sub.3 ; andf. recovering SiO.sub.2.nH.sub.2 O of a purity of at least 90%.