hey could someone help me please this is pretty easy you just need to fill in the information with made up things but i gotta work on something else, thank u sm!

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.