Massive Basalt with Lherzolite Low viscosity – Little gas content Size: 7cm Basalt with void filled with globular Witherite Low viscosity – Low gas content Size: 19 cm Glassy Basalt Quenched lava of low viscosity and little gas content Size: 12 cm Vesicular Olivine Basalt Low viscosity – high gas content Size: 15 cm Scoria - Extremely vesicular basaltic lava Low viscosity – Very high gas content Size: 15 cm Pumice – Froth of silica-rich volcanic glass High viscosity – high gas content Size: 12 cm Crystal Lithic Tuff – Pyroclastic rock High viscosity - Explosive volcanism due to very high gas content Size: 12 cm Welded Tuff – Pyroclastic rock High viscosity - Explosive volcanism due to very high gas content Size: 20 cm