Iodine-131 (usually in the chemical form of iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate ingested iodine, where it is kept for periods longer than this isotope's radiological half-life of eight days.
Magma is composed of molten rock and is stored in the Earthâs crust. Lava is magma that reaches the surface of our planet through a volcano vent. Lava flow, Hawai. Courtesy of the U.S. Geological Society.agma is composed of molten rock and is stored in the Earthâs crust. Lava is magma that reaches the surface of our planet through a volcano vent. Lava flow, Hawai. Courtesy of the U.S. Geological Society.
Noun. 1. lava-rock that in its molten form (as magma) issues from volcanos; lava is what magma is called when it reaches the surface. aa-a dry form of lava resembling clinkers.pahoehoe-freely flowing lava.pillow lava-lava that hardened in rounded shapes suggestive of pillows; believed to result from underwater eruptions.. lava-rock that in its molten form (as magma) issues from volcanos; lava is what magma is called when it reaches the surface. aa-a dry form of lava resembling clinkers. pahoehoe-freely flowing lava. pillow lava-lava that hardened in rounded shapes suggestive of pillows; believed to result from underwater eruptions.