vitrains
/ˈvaɪtreɪnz/
noun
- A type of coal that is shiny, black, and glass-like, formed from plant material under heat and pressure.
- Geologists study vitrains to understand the ancient forests that existed millions of years ago.
- When burned, vitrains produce a bright flame and less smoke than other types of coal.
- The miner pointed to a seam of vitrains in the coal face, gleaming like polished obsidian.