Mark Kurlansky's recent book, Salt: A World History, made a lot of people realize that this innocuous, edible rock that we humans love to sprinkle on just about everything we stick in our mouths is intimately tied to almost every aspect of human history. In Pure: Grains of Salt artist Haninga Thiel takes a more creative stance. Yet like Kurlansky's book, Thiel's conceptual installation, which has been showing for a couple weeks at [AC]2, explores and illuminates the many surprising facets of this ordinary, extraordinary household product. The exhibit will be up through Aug. 17. 842-8016.