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

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

Cryptotephra are signature volcanic glass shards that can range from 80-20 microns in size, which is smaller than the diameter of a human hair.

From Science Daily • Mar. 20, 2024

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 hydrochloric acid and tiny particles of volcanic glass released into the air can cause skin, eye and respiratory tract irritation.

From Seattle Times • Sep. 30, 2021

Sapiens bands that lived on the island of New Ireland, north of New Guinea, used a volcanic glass called obsidian to manufacture particularly strong and sharp tools.

From "Sapiens: A Brief History of Humankind" by Yuval Noah Harari