leepala asked:

what is your favorite volcanic rock


volcanic rocks are prob some of my favorite rocks of all rocks, so i can’t really answer this question definitively and let me show you why:

this is one of my favorite charts Of All Time re: these types of things, because it’s a (very) simplified but really gr9 visual for people who aren’t as well ‘versed in volcanic rocks as someone like me.

basically what this says is there are four Main Types (there are other subcategories that are a mixture of these types, and really it’s currently impossible for us to completely define magma content) of volcanic rocks, broken into categories by approximate silica (we use silica because silica makes up the greatest amount of content in magma by percentage NOT IRON SO CHILL OUT FANDOM PEOPLE WHO HAVE MAGS THROWIN LAVA AROUND WHAT THE HELL) content: basalt, andesite, dacite, and rhyolite.

rocks that fall more towards the basalt end of the scale are considered mafic, and rocks that fall more towards the rhyolite end of the scale are considered felsic. anything in between is termed intermediate. HOWEVER, as you can see by the % silica content, no two basaltic (or andesitic, dacitic, rhyolitic, etc.) rocks will look EXACTLY THE SAME, even if they came from the same parent magma (they’ll be pretty damn similar in that case, though). a lot of factors go into how and when magma mixes and cools and makes rocks, and trust me when i say that unless you are interested in studying petrology you literally do not care. lmfao.

anyway, going back to the rad chart, the more silica, the hotter but less viscous (thick and syrupy) the lava is. so basaltic lava flows, which are most of what we see on Hawaii, is super hot and travels fast - like all the houses that got consumed by lava flows very recently.

the less silica, the cooler but more viscous the lava is. the fun thing about this, though, is that higher viscosity = higher explosivity due to a higher amount of trapped gasses in the magma, which means that this shit makes bigger explosions when it erupts. B^J