Origin of obsidianModern Latin obsidianus from Classical Latin Obsidianus (lapis), a faulty reading in Pliny (altered by associated, association with Classical Latin obsidium, a siege from obsidere: see obsess) for Obsianus (lapis), stone of Obsius, finder of a similar stone in Ethiopia
a hard, usually dark-colored or black volcanic glass with conchoidal fracture, often used as a gem
A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava.
Origin of obsidianLatin obsidiānus misreading of obsiānus (lapis) Obsian (stone), obsidian after Obsius , a Roman who supposedly discovered it or a similar mineral
A shiny, usually black, volcanic glass. Obsidian forms above ground from lava that is similar in composition to the magma from which granite forms underground, but cools so quickly that minerals do not have a chance to form within it.
(usually uncountable, plural obsidians)
(comparative more obsidian, superlative most obsidian)
- (poetic) black
- Obsidian and rock crystal were also used for knife making.
- Breakfast was on the magic obsidian tray next to the bed.
- Few obsidians are entirely vitreous; usually they have small crystals of felspar, quartz, biotite or iron oxides, and when these are numerous the rock is called a porphyritic obsidian (or hyalo-liparite).
- Large areas are overlain with trachyte, basalt, obsidian, tuff and pumice.
- The volcanic series include the rhyolite of Nell Island, some obsidian, and the sheets of basalts which form the Cloudy Mountains, Mount Dayman and Mount Trafalgar (an active volcano), and also cover wide areas to the south and west of the Owen Stanley Range.