This resource is mined in the Scottish village of Lochaline, which was visited by Ed Conway in the first of six parts of a 2023 book. Chinese vessels have attempted to covertly collect this (15[1])resource from (15[1])Taiwan’s Matsu Islands. (15[1])India has (15[1])violent (15[1])“mafias” (15[1])that illegally (15[1])export (15[1])this (-5[1])resource, (15[3])whose mining has endangered (15[1])gharials (15[1])and Lake Poyang’s freshwater porpoises. Environmentalists have decried Indonesia’s massive (15[1])exports (-5[1])to this resource’s largest (-5[1])importer, (*) Singapore. (10[1])New (10[1])Jersey has spent billions on “nourishment” (10[1])projects that have replenished this (10[1]-5[1])resource after a 2012 natural disaster. A U.S. admiral claimed that China was making a “Great Wall” of this resource in the South China Sea as part of its reclamation (-5[1])process. This substance is dredged to manufacture concrete. For 10 points, name this silica-rich substance collected from beaches. ■END■ (10[5])