fire-formed rock
nounUK /ˈfaɪə fɔːmd rɒk/
US /ˈfaɪər fɔːrmd rɑːk/
Rock that was made hard by heat from fire or lava.
The volcano left behind fire-formed rock that was dark and smooth.
OTHER MEANINGS
2. Rock baked hard by a campfire or forest fire.
We found fire-formed rock around the old campsite.
3. Rock shaped or cracked by intense heat.
The fire-formed rock split into thin layers.
4. A stone used in fire pits because it can take high heat.
They lined the fire pit with fire-formed rock.