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Oh no! A volcano has erupted, there is so much lava!
Many different types of rock will be created but they are all going to be igneous do to extreme heating and cooling of rock. this creates crystals.
It is very windy outside today
This is a sedimentary rock. it was created from erosion mostly from wind and sand. 
This i a mining site,  people mine for ores and minerals here.
Most rocks found here are metamorphic. Because of the extreme pressure, it compacts the rock squishing it and smoothing it.
Igneous rock is typically the hardest and most metallic.
Usually after volcanic eruptions,  massive amounts of obsidian is left behind. Obsidian is a igneous rock
Igneous rock can also be formed deep underground if its hot enough and in the core or earth
Sedimentary rock is by far the softest because of the ongoing erosion. It is usually sandy and has the most variety of minerals
Rivers can also create sedimentary rock. Because water is moving throughout the riverbeds and rocks, The water slowly erodes down rock creating sand, silt and a large amount of small minerals
Metamorphic rock usually has visible layers. After enormous amounts of time underground, these rocks get sandwiched together with so much pressure that it flattens out becoming super hard.