Related Clues:

• Source of leucite and rhyolite
• Igneous rock, originally
• Obsidian source
• Type of lamp
• Volcanic outpouring
• Pompeii destroyer
• Efflux from Etna
• Pelée spew
• Slow flow
• Igneous rock source
• Pompeii was covered in it
• Volcanic effluent
• Gas-grill rock
• Hot flower
• Rock that rolls?