specimen scoria, igneous rock of volcanic rock

andesitic asia bar basalt basaltic brown bubbles centimeter central chemical composition cone consists contain crust crystal crystals cynder earth element engineering geochemical geological geologist geology glass highly holes igneous indonesia isolated java lava light may microscope mineralogy minerals mountain not ovale oxide photograph pumice purplis pyroclastic red rock rough rounded sampling schale scoria scoriaceous scrub specimen structure surface survey texture textured that various vesicular volcanic volcanology weighs which