Closeup picture of a Limu o Pele volcanic sheet glass fragment.
Limu o Pele or Pele's seaweed (Hawaiian, literally, "seaweed of Pele", after Pele the Hawaiian fire goddess of volcanoes) is a geological term for thin sheets and subsequently shattered flakes of brownish-green to near-colourless volcanic glasslava spatter that commonly resemble seaweed in appearance, that have been erupted from a volcano. Limu o Pele is formed when water is forced into and trapped inside lava, as when waves wash over the top of the exposed flows of the molten rock. The water boils and is instantly converted to steam, expanding to form bubbles within the lava. The lava rapidly cools and solidifies as the bubbles grow. The volcanic glass bubbles burst and are dispersed by the wind, showering flakes of glass downwind.