Obsidian

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.

It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth. Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (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. Obsidian is hard and brittle; it therefore fractures with very sharp edges, which had been used in the past in cutting and piercing tools, and has been used experimentally as surgical scalpel blades.

Read more about ObsidianOrigin and Properties, Occurrence, Historical Use, Current Use

Other articles related to "obsidian":

Aguateca - Material Culture - Obsidian
... Obsidian was a highly valued material in Classic Maya society, and possession of it was indicative of high status ... The rulers of Aguateca controlled the main access to obsidian in the city while the procurement and distribution of obsidian may have been administered by the royal court ... number of stronger and more substantial obsidian crafted blades than those who lived in smaller residences ...
Speech Sounds - Plot Summary
... It is then she meets Obsidian, a man in a police uniform who stops to restore order and then offers her a ride in his car ... Before long, Rye learns that Obsidian can still read a map, and she struggles with an intense feeling of jealousy and an urge to kill him ... Rye asks Obsidian to return home with her, and he reluctantly agrees ...
Chivay Obsidian Source
... The Chivay obsidian source (71.5355° S, 15.6423° W, 4972 masl) is the geological origin of a chemical group of obsidian that is found throughout the south-central Andean highlands ... Analysis (NAA) have shown that the Chivay obsidian source, also known as the Cotallalli type or the Titicaca Basin type, makes up over 90% of the obsidian artifacts analyzed from ... Obsidian from the Chivay source is found in large and homogeneous nodules in a high altitude volcanic depression approximately ten km to the east of the ...
Obsidian - Current Use
... US Food and Drug Administration (FDA) for use on humans, obsidian is used by some surgeons for scalpel blades, as well-crafted obsidian blades have a ... enough microscope when examined even under an electron microscope an obsidian blade is still smooth and even ... One study found that obsidian incisions produced narrower scars, fewer inflammatory cells, and less granulation tissue in a group of rats ...
Anahim Peak - Area and History
... Anahim Peak was a significant source of obsidian for the Nuxalk, Tsilhqot'in, and Dakelh peoples ... Obsidian was seriously needed, because extremely sharp arrowheads and cutting knives could be made from it ... Anahim obsidian was traded widely all over the BC Interior and up and down the Coast from Bella Coola ...