naturglas

Naturglas, meaning "natural glass" in German, refers to glass that is formed through natural geological processes. Unlike manufactured glass, which is typically created by melting sand and other minerals at high temperatures, naturglas is a product of volcanic activity or meteorite impacts.

The most common form of naturglas is obsidian, a volcanic glass that forms when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. Obsidian is usually black in color, though it can also be brown, gray, or even green. It is known for its sharp edges, which made it a valuable material for toolmaking by ancient civilizations.

Another type of naturglas is tektite. Tektites are small, irregular glassy objects that are formed from terrestrial rock that was melted by the extreme temperatures and pressures of a meteorite impact. The molten rock is then ejected into the atmosphere and cools rapidly as it falls back to Earth. Tektites are typically dark brown or black and can be found in scattered strewn fields around the world, indicating the locations of past impact events.

While natural glass has been used by humans for millennia, its occurrence is limited to specific geological settings. The study of naturglas provides insights into volcanic processes, impact events, and the early history of glass formation on Earth.