Have you ever seen those things called rocks on the side of the road? You most likely have. But have you ever stopped and researched about them? Probably not; but I did so you don’t have too. Here are the 3 main types of rocks.

The first type of rocks I’m going to talk about are igneous rocks. Igneous rocks are volcanic rocks that can be separated into 2 categories, which are extrusive and intrusive. Extrusive igneous rocks are formed by magma coming up to the surface or near the surface and cooling very fast, hints the “ex” in extrusive. Intrusive igneous rocks are formed by magma deep in the earth slowly cooling into igneous rock. When this igneous rock is exposed to water and/or wind it erodes. After it erodes, it can compress into a different kind of rock. That rock is sedimentary rock.

Sedimentary rock is a type of rock that is a combination of many sediments which hints the “sediment” in sedimentary. They are also the most common rock to find fossils in since it’s made of preexisting sediments that have been compressed enough to stay together. The fossils just get caught up in it. Sedimentary rocks are found everywhere, from oceans, to deserts, and even caves. They are the most common rocks to be exposed on the surface, but abundance-wise igneous rocks are the most common. When either igneous rocks or sedimentary rocks get exposed to a bunch of heat and pressure they create metamorphic rocks.

Metamorphic rocks are a type of rock that started as either igneous or sedimentary. When either are subjected to too much heat and pressure they turn into metamorphic rocks. Some common metamorphic rocks include phyllite, schist, gneiss, quartzite and marble. Despite the immense heat they experience they do not melt, but the chemicals they contain change their forms. The name metamorphic comes from Greek words that mean “change of shape”.

So, next time you see a random rock on the side of the road just know it’s either an igneous rock, metamorphic rock, or a sedimentary rock. If it’s kinda sandy looking, almost like you could break it if you wanted to, it’s probably sedimentary. If it has almost a “squashed” texture it’s probably metaphoric. And finally, if you see one with distinct and large crystals, it’s probably an igneous rock. If you want to learn more about the rock cycle, visit Ugc.Berkly.