The present invention discloses an exfoliative clay and a derivative thereof and a method for producing the same. The exfoliative clay is formed by emulsion exfoliating an inorganic layered silicate clay with an amphibious intercalating agent by powerfully stirring at 60-180 C. and not less than 14.7 psig. The amphibious intercalating agent is obtained by copolymerizing polyoxyalkylene amine having molecular weight over 1,800 and polypropylene-grafting-maleic anhydride (PP-g-MA). Before emulsion exfoliation, the intercalating agent is acidified with an inorganic acid. The acidification is the key step for obtaining nanoscale of emulsifying particles less than 100 nm for the exfoliation. The exfoliative clay can be further extracted with a hydroxide or a chloride of alkali metal or alkaline-earth metal to obtain a derivative in the form of nanosilica plates which is free of organic portions.