Pumice thin section slide exhibiting the highly vesicular nature of this extrusive igneous rock. Pumice forms when super heated, highly pressurised lava is violently ejected from a volcano. The porous nature of pumice occurs because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases (including water and CO2) that are dissolved in the lava, causing the gases to rapidly exsolve. The simultaneous cooling and depressurization freezes the bubbles in the matrix. Pumice lavas tend to be silicic or felsic which are highly viscous thus do not allow the gas bubbles to escape efficiently. This material was collected from the Lipari islands of Italy. Each section is made to 30 microns thickness and the glass is 46 x 27 mm in size with a cover slip. Supplied in a protective card sleeve with a label, ideal for microscopy and educational purposes.