volcanic glass

American  

noun

1. a natural glass produced when molten lava cools very rapidly; obsidian.

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volcanic glass British  

noun

1. any of several glassy volcanic igneous rocks, such as obsidian and pitchstone

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volcanic glass Scientific  

1. Natural glass produced by the cooling of molten lava too quickly to permit crystallization. Obsidian is a type of volcanic glass.

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Etymology

Origin of volcanic glass

First recorded in 1830–40

Example Sentences

See Examples For:

volcanic glass

These microscopic pieces of volcanic glass are invisible to the naked eye, making them extremely difficult to find.

From Science Daily ● May 11, 2026

One gem is thought to be a rare, 2nd Century head of the Greek hero Hercules made from obsidian, a type of volcanic glass.

From BBC ● May 27, 2024

The ancient Maya — who called eclipses “broken sun” — may have used dark volcanic glass to protect their eyes, said archeologist Arturo Montero of Tepeyac University in Mexico City.

From Seattle Times ● Oct. 13, 2023

The sword, also on display in the exhibit, is a flat wooden club with a groove where razor-sharp obsidian - a type of volcanic glass - would have been wedged in.

From Reuters ● Sep. 29, 2023

The knives were old things: the hilts were made of bone, while the blades were chipped, volcanic glass, black as jet, with white snowflake-shapes frozen forever into the obsidian.

From "Stardust" by Neil Gaiman