Crustal rocks are primarily made up of silicate minerals. These minerals are composed of silicon and oxygen, with varying amounts of other elements like aluminum, iron, calcium, sodium, potassium, and magnesium.

Here's a breakdown:

* Igneous rocks: Formed from the cooling and solidification of molten rock (magma or lava). They are classified based on their mineral composition and texture, with common examples being granite, basalt, and rhyolite.

* Sedimentary rocks: Formed from the accumulation and cementation of sediments (like sand, mud, or organic matter). They often contain fossils and are important for studying Earth's history. Common examples include sandstone, limestone, and shale.

* Metamorphic rocks: Formed when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are transformed by heat, pressure, or chemical reactions. Examples include marble, slate, and gneiss.

While silicate minerals dominate crustal rocks, other minerals, like oxides, carbonates, and sulfides, can also be present in smaller amounts.