Lets break it out the Science.
There are Three Natural Rock Types. And how they form are very different.
Igneous Rocks - Formed from Molten Rock [Lava cooling] and then Solidifies. So Needless to say you can have special gems and rocks that form around Lava. This would imply Lava could form on the surface which could imply Volcanic eruptions-- do our worlds coming up all have lava on them? If not, how do the lands form?
Special note: You have Intrusive Igneous rocks and Extrusive Igneous rocks as well. Pending if they form on the surface and below.
Examples of Intrusive: Diabase, diorite, habbro, granite, pegmatite, and peridotite.
Examples of Extrusive: Andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria and tuff.
Sedimentary Rocks: 
are from when particles settle out of Water or air by precipitation of minerals from water. This happens in layers of course. So this means low-water areas
Examples can be: Shale, Limestone, Sandstone, Conglomerate, Breccia and Siltstone. Now you can of course make Chemical Sedi stone/rocks. Like Chert, Dolomites, Flint, and Rock salt. And going more organic of course, we have Coal, Diatomite, Dolomites and chalk.
And then we have good ol’ Metamorphic Rocks. Metamorphic rocks form when sedimentary, igneous, or pre-existing metamorphic rocks are changed by heat, pressure, and chemically reactive waters. These rocks are identified by their minerals and texture.
Some examples of this is: Manhattan Schist, Slate, Gneiss, Marble, Quartzite, and Phyllite
So what happens to the rest. We have Sand, gravel, Ice, Wood… Trees are totally another kind of thing for another topic, same as food.
