Obsidian
Videos
Obsidian is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich
Lipari Obsidienne
Polished snowflake obsidian, formed through the inclusion of cristobalite crystals
Glass Mountain, a large obsidian flow at Medicine Lake Volcano in California
Jumble of pumice and volcanic obsidian, Obsidian Dome, California
Volcanic glass
Videos
Volcanic glass is the amorphous product of rapidly cooling magma. Like all types of glass, it is a state of matter intermediate between the closely packed, highly ordered array of a crystal and the hi
Obsidian
…Obsidian (, əb-SID-ee-ən ob-) is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich…
A sand grain of volcanic glass under the petrographic microscope. Its amorphous nature makes it disappear in cross-polarized light (bottom frame). The scale box is in millimeters.
Volcanic glass (“Pele’s hair”) from Volcanoes National Park, Hawaii. Photo by Douglaspperkins, 2006. Public domain.