When it comes to outdoor seating on active volcanoes, choosing the right materials is critical for safety and durability. Traditional furniture simply won't withstand the extreme heat, corrosive gases, and unpredictable conditions. Here are the top materials recommended for such harsh environments:

1. Lava Rock: Naturally resistant to extreme heat, lava rock can be carved into benches or seating structures. Its porous nature also helps dissipate heat.

2. Stainless Steel (Grade 316): This high-grade steel resists corrosion from volcanic gases and can handle intense temperatures with proper insulation.

3. Ceramic Composites: Specially engineered ceramics offer excellent thermal resistance and durability against ash and acidic conditions.

4. Basalt Fiber Reinforced Polymer (BFRP): Lightweight yet incredibly strong, BFRP is resistant to heat and chemical erosion.

5. Refractory Concrete: Designed to withstand extreme temperatures, this concrete variant is ideal for permanent seating installations.

For added safety, avoid plastics or untreated wood, as they can melt or combust. Always prioritize materials tested for volcanic environments to ensure longevity and safety.