obsidian
nounUK /əbˈsɪdiən/
US /əbˈsɪdiən/
Obsidian is a shiny black rock that forms when hot lava cools very fast.
The arrowhead was made from a sharp piece of obsidian.
RELATED WORDS
OTHER MEANINGS
2. A deep, glossy black color.
She painted her nails a striking obsidian shade.
3. Something extremely dark or black in appearance.
The obsidian waters of the lake reflected no light.
4. In fantasy stories, a hard dark material used for weapons or armor.
The knight carried a sword forged from obsidian.