Description
A fulgurite, or lightning tube, is a hollow tube of molten rock or sand, often consisting largely of lechatelierite. This is formed by the intense heat generated by lightning striking quartz-rich soils. Strictly speaking, it can be considered an example of a metamorphic rock formed by contact metamorphism. Fulgurite takes its name from the Latin word fulgur, fulguris, "lightning, lightning," which could be translated as "lightning stone" or "thunder stone." In earlier times, fulgurite was thought to be lightning itself that had struck. The exterior of a fulgurite is usually rough and may be covered with grains of sand, while the interior is often smooth. Fulgurites form primarily in sandy soils in areas with high thunderstorm activity. In principle, a fulgurite can form in any mineral soil type. Although fulgurites are common, they are rarely found. They are often difficult to detect and also very brittle, so a fulgurite often breaks into pieces during excavation. Fulgurites are never found on dune tops in desert areas, but always in the hollows between the dunes. This is because lightning strikes there where the groundwater is closest to the surface. Fulgurites have a diameter of up to several centimeters and can reach lengths of many meters. In 1942, a three-meter-long fulgurite was found near Hulshorst on the Veluwe. In 1952, a lightning tube approximately ten meters long was found in Zonhoven.
