I would sort them into the categories of metamorphic rock, sedimentary rock, and igneous rock.
Igneous rocks are made from the cooling and solidifying of lava or magma. Pumice is one of these rocks, it's made from lava being thrown out of volcano, and rapidly cooling. Obsidian and granite the other igneous rocks in the list.
Sedimentary rocks are made from the sedimentation of smaller particles. Coquina limestone is one of these - it's made from the sedimentation of the shells of dead animals.
Metamorphic rocks are rocks which are created by extreme heat and pressure. Essentially, they used to be a different kind of rock, and now they're metamorphic rocks. Gneiss and soapstone are both metamorphic rocks.
So here are your final answers:
Igneous: Granite, Obsidian, Pumice
Sedimentary: Coquina limestone
Metamorphic: Gneiss, Soapstone
Hope this helped!
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