Interesting fact: Fresh lava may glow bright orange, but its weight is controlled more by chemistry and gas content than by how hot it looks.
The answer: Lava typically weighs about 2,600 to 3,100 kilograms per cubic meter, depending on composition and trapped gases. Basaltic lava is often near the lower end, while denser silica-rich material can be heavier.
Weighing lava directly is dangerous because it is extremely hot and often moving, so geologists rely on sample density and field volume estimates. Lava weight matters for eruption models, flow forecasting, structural loading, and understanding how volcanic landscapes build up over time. Even a seemingly small lava flow can represent a staggering amount of mass.
