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What is obsidian?

In: Geology [Edit categories]

Answer:

A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava.

The curved fracture surfaces are more correctly termed
conchoidal fractures and the "glass" is said to have a "vitreous" texture as the material cools so rapidly that crystals do not have time to form.

First answer by 4Jays. Last edit by SBDW1. Contributor trust: 228 [recommend contributor ]. Question popularity: 2 [recommend question].

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Relevant answers:

Where is obsidian from?
obsidian is molten glass from inside a volcano that, when it is expelled from the volcano and cooled down, forms the igneous rock obsidian!
Is obsidian dense?
Yes, obsidian is dense. It is, therefore, heavy (compared to Pumice, which can float).
Is Obsidian rough?
No.
Is obsidian poisonous?
No. But ingesting fractured obsidian could be harmful to the digestive system. If in doubt, contact a medical professional.
What is the geology of obsidian?
Obsidian is volcanic glass. unusually amongst the various rocks and minerals it is made of one single piece with no individual grains. this is due to it being cooled extremly rapidly from a magma...