What does obsidian mean?
Obsidian is a naturally occurring volcanic glass, most often black, created when lava cools so quickly that mineral crystals cannot form. Because it can be fractured into exceptionally sharp edges, obsidian was valued by many prehistoric and early historic communities for making knives, spear points, scrapers, and other tools. It was also polished for beads, blades, mirrors, and decorative objects. Today the word appears frequently in archaeology, geology, lapidary, and craft discussions. It should not be confused with onyx: obsidian is volcanic glass, while onyx is a banded variety of chalcedony. In general use, obsidian often conveys qualities of darkness, hardness, sharpness, and antiquity, as well as a close connection with volcanic landscapes and early human technology.
A dark volcanic glass formed by the rapid cooling of lava, or a piece or worked object made from it.
"The blade was made from obsidian and had been finely shaped by pressure flaking."
Use obsidian as an uncountable noun for the material; use obsidians for individual pieces when needed.
Made of, consisting of, or relating to obsidian.
"The craftswearer's obsidian tools were traded across a wide network of settlements."
The adjective is especially common in archaeological, geological, and craft-related descriptions.
The plural is used for individual pieces or objects made of obsidian; the material itself is normally uncountable.
"The collection includes several obsidians with finely polished edges."
Obsidian is a glass made by fire: a sudden chill can lock lava into a smooth, glassy material sharp enough to cut with.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does obsidian come from?
The English word comes through French and Latin from Greek ὀψιδιανός (obsidianos), an ancient term associated with a black or glassy stone. Latin used the form obsidianus, and French supplied obsidienne before the word entered English. The deeper origin of the classical name is obscure, so more specific claims about its earliest Greek derivation should be treated cautiously.
Related word forms
How obsidian is actually used
Obsidian is usually treated as an uncountable material noun when referring to the substance, while the plural obsidians can refer to individual pieces or objects. The adjective obsidian is commonly used in archaeological, geological, and craft contexts.
Easily confused with obsidian
Obsidian is a volcanic glass, whereas onyx is a banded form of chalcedony; both may be black and polished for use in jewelry.