Question

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. What attribute would you use to sort these rocks? Which rocks would be in each category? Rocks: obsidian, coquina limestone, granite, soapstone,pumice, and gneiss.

Answer 1

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!