Recent Examples on the WebThe volcanic ash added a mineral called phillipsite to the concrete, and a study published Monday in the American Mineralogist reveals that aluminous tobermorite crystals grow in the Roman concrete when it is exposed to water. Jay Bennett, Popular Mechanics, 5 July 2017 The tests showed a rare chemical reaction, with aluminous tobermorite crystals growing out of another mineral called phillipsite. The Washington Post, NOLA.com, 6 July 2017 The tests revealed a rare chemical reaction, with aluminous tobermorite crystals growing out of another mineral called phillipsite. Ben Guarino, Washington Post, 4 July 2017