Abstract The palygorskite-sepiolite group of clay minerals has a wide range of industrial applications. Sepiolite, in particular, has desirable sorptive, colloidal-rheological, and catalytic properties which can be modified and improved by appropriate thermal and acid treatments to extend its range of commercial uses. Sepiolite from the Vallecas deposit in Spain has been mined since the late 1600s, where it was used in the manufacture of pipes and later as a ceramic paste in the production of porcelain. Currently, the Vallecas sepiolite is used as a deodorizing agent for animal wastes, a decolorizing agent for mineral and vegetable oils, an adsorbent of undesirable polar compounds in cigarette filters, an adsorbent for toxins in the gastrointestinal tract, a catalytic support in petrochemical processes, a thixotropic agent in cosmetic preparations, a suspension agent in fertilizers and drilling muds, a filler and carrier in rubber and animal feeds, and an excipient in pharmaceutical products.