Activated charcoal and zeolites are both categorized by having pores equal to or smaller than what size?
Activated carbon Activated carbon, also called activated charcoal, is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption or chemical reactions. "Activated" is sometimes substituted with "active".
Sillar Sillar is a variety of rhyolite, which is a type of volcanic rock. Although sillar is of rhyolitic composition, it has been erupted from volcanoes which mostly erupt andesite lava, and sillar contains small fragments of andesite. A pink variety of sillar owes its colour to crystals of hematite within the rock. A white variety lacks these hematite crystals. Sillar is found as pyroclastic flow deposits of tuff near volcanoes in southern Peru, for example the now-extinct Chachani volcano which erupted flows of sillar during the Pleistocene epoch.