[Elamur Dictionary](https://md.dictionary.elamur.ai/free/en/) · [this page in HTML](https://dictionary.elamur.ai/free/en/english/obsidian/)

[dictionaries](https://md.dictionary.elamur.ai/free/en/) / [English](https://md.dictionary.elamur.ai/free/en/english/) / [O](https://md.dictionary.elamur.ai/free/en/english/o/) / obsidian

# obsidian

noun (obsidian; uncountable)

«obsidian» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

1. Obsidian is a hard, shiny black (or dark) natural glass that forms when lava from a volcano cools very quickly. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#m1)
2. Obsidian was used long ago to make very sharp knives, arrowheads and mirrors. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#m2)

### In the lessons

In science lessons on rocks, obsidian is an igneous rock (made from cooled lava) that cooled too fast for crystals to grow, so it is glassy; when it breaks it has very sharp curved edges. In history, the Aztecs and other peoples made tools and mirrors from it. In the game Minecraft, obsidian is a very hard block. Phrases: «obsidian blade», «volcanic glass».

### Examples

- Obsidian is black volcanic glass. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#x1)
- Obsidian forms when lava cools very quickly. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#x2)
- Ancient people made sharp arrowheads from obsidian. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#x3)
- The museum had an Aztec mirror made of obsidian. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#x4)
- In Minecraft you need obsidian to build a portal. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#x5)
- Obsidian is an igneous rock. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/#x6)

### Note

Uncountable: «a piece of obsidian». Pronounced ob-SID-ee-un. Safety: broken obsidian is sharper than a knife, so handle with care.

## On Mova

- [Trees and pragmatics of «obsidian» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/O/obsidian/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«obsidian» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/obsidian.html) on Mova free.