Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. source
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.
Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. source
Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth.
Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows. source
Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows.
The chemical composition of Obsidian (high silica content) induces a high viscosity and polymerization degree of the lava. source
The chemical composition of Obsidian (high silica content) induces a high viscosity and polymerization degree of the lava.
The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth. source
The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth.
Obsidian were used in the past in cutting and piercing tools. source
Obsidian were used in the past in cutting and piercing tools.
Obsidian has been used experimentally as surgical scalpel blades. source
Obsidian has been used experimentally as surgical scalpel blades.
Among the various forms of glass we may reckon Obsian glass, a substance very similar to the stone found by Obsius in Ethiopia. source
Among the various forms of glass we may reckon Obsian glass, a substance very similar to the stone found by Obsius in Ethiopia.
Pure obsidian is usually dark in appearance, though the color varies depending on the presence of impurities. source
Pure obsidian is usually dark in appearance, though the color varies depending on the presence of impurities.
Obsidian becomes progressively hydrated when exposed to groundwater, forming perlite. source
Obsidian becomes progressively hydrated when exposed to groundwater, forming perlite.
Obsidian can be found in locations which have experienced rhyolitic eruptions. source
Obsidian can be found in locations which have experienced rhyolitic eruptions.
Obsidian is used for ornamental purposes and as a gemstone. source
Obsidian is used for ornamental purposes and as a gemstone.
Obsidian was used on Rapa Nui (Easter Island) for edged tools such as Mataia and the pupils of the eyes of their Moai (statues). source
Obsidian was used on Rapa Nui (Easter Island) for edged tools such as Mataia and the pupils of the eyes of their Moai (statues).
In Chile obsidian tools from Chaitén Volcano have been found as far away as in Chan-Chan 400 km (250 mi) north of the volcano and also in sites 400 km south of it. source
In Chile obsidian tools from Chaitén Volcano have been found as far away as in Chan-Chan 400 km (250 mi) north of the volcano and also in sites 400 km south of it.
Neutron activation analysis (NAA) on the obsidian found at this site helped to reveal trade routes and exchange networks previously unknown. source
Neutron activation analysis (NAA) on the obsidian found at this site helped to reveal trade routes and exchange networks previously unknown.