It is generated when gas-rich lava comes into contact with water on the seafloor. Rapid cooling traps gas bubbles inside the rock, creating its characteristic cavity-filled structure.

⚙️ Main Features

• Extremely lightweight: Floats in water.

• High porosity: Filled with small holes (vesicles).

• Color: grey / black

🌊 Underwater peculiarity

When the eruption occurs underwater, the stone can:

• Float to the surface forming “pumice islands.”

• Be transported by ocean currents for thousands of miles.

🧪 Composition

Mainly composed of:

• Silica (SiO2)

• Aluminum

• Small amounts of iron, calcium, sodium, and potassium