Minerals!
Minerals are the "building blocks" to our earth's crust and rocks. The most commonly known minerals are the quartz, feldspar, hornblende, and mic.
The two most common minerals are:
Quartz
Feldspar
Here is more info:
http://www2.nature.nps.gov/geology/usgsnps/rxmin/mineral.html
Rocks:
Rocks are a composition of minerals that are created by weather, heat, and other natural causes. Rocks are classified into three different categories based on the way that they were composed: Igneous Rocks(Cooled from lava), Sedimentary Rocks(sediment molded together), and Metamorphic Rocks(go through changes to make a more crystalized rock).
Granite(Igneous Rock)
Hematite (Sedimentary Rock)
Slate(Metamorphic Rock)
