Here's why:

* Scoria: Scoria is a type of extrusive igneous rock, meaning it cooled and solidified from lava that erupted onto the Earth's surface. It's characterized by its vesicular texture, meaning it contains many air bubbles (vesicles) trapped within the rock.

* Scoria's mineral composition can vary depending on the composition of the original magma, but it typically contains minerals like pyroxene, olivine, and plagioclase feldspar.

* It's commonly associated with basaltic lava, which is rich in iron and magnesium.

* Rhyolite: Rhyolite is also an extrusive igneous rock, but it's formed from felsic magma (rich in silica). This results in a very different mineral composition than scoria.

* Rhyolite typically contains minerals like quartz, alkali feldspar, and plagioclase feldspar, with smaller amounts of biotite and hornblende.

* It's often associated with explosive volcanic eruptions and can have a glassy or porphyritic texture.

In summary: While both are extrusive igneous rocks, scoria and rhyolite have different mineral compositions due to the different types of magma they originate from. Scoria is mafic (rich in iron and magnesium), while rhyolite is felsic (rich in silica).