I AM SO GLAD YOU ASKED!!!
These are all ROCKS. DEFINITELY ROCKS. Ask for my top 10 minerals seperately.
1. SKARN - METAMORPHIC. I love skarn. Probably for obvious reasons. We found a super bad skarn deposit in a cave, and that's how we made cell phones! Also, @senku-ishigami-official said "Skarn is a bunch of different shit," but that's what makes it so cool! It's every rock in one rock!
2. HALITE - SEDIMENTARY. This one's on here because it's edible.
3. ANTHRACITE - METAMORPHIC. This one's just coal, but like, really awesome coal. It's over 87% carbon. That's a lot of carbon.
4. PERIDOTITE - IGNEOUS. Green! It's the best to look at, in my opinion, anyway. Can you even believe it's a rock? Not a gemstone? Of course, it's named after a gemstone, though.
5. IRON ORE - SEDIMENTARY. Yeah. I know this one looks like a whole category, but the thing is, sedimentary rocks can be basically anything! Iron-rich Sedimentary Rocks is a valid classification (sedimentary rocks are usually grouped either by origin of composition). I love iron. Great metal.
6. QUARTZITE - METAMORPHIC. Quartzite had to contain at least 80% quartz to be called that, and we used to use it for tools! It's pretty hard and looks nice.
7. OBSIDIAN - IGNEOUS. This is both rock and glass, isn't that bad?!? it has a Mohs Hardness of 5 or 6, and it's another one we used for tools. This one specifically for weapons and knives. Really useful rock.
8. PUMICE - IGNEOUS. I thought this was a coral when I first found it. This stuff can be pretty light.
9. LIMESTONE - SEDIMENTARY. Lime is really important. Senku told Taiju that so much that I caught him eating a whole lime. By itself. The citron. Not the rock. But the rock is what's important.
10. CHALK - SEDIMENTARY. You can write with this one, so it's useful as hell. Also Suika's dog's name. Because he used to be entirely whitish.
THERE YOU GO! MY TOP 10 ROCKS!!!