Pumice is a volcanic rock that is formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases (including water and CO2) dissolved in the lava, so that they rapidly exsolve (like the bubbles of CO2 that appear when a carbonated drink is opened). The simultaneous cooling then freezes the bubbles in the matrix and thus forms Pumice.
Chemical analysis :
| SiO2 |
: |
50% |
| Fe2O3 |
: |
21-26% |
| Na2O |
: |
6% |
| K2O |
: |
3.5% |
|
