The most common element found in solid form within the Earth's crust is oxygen.

Here's why:

* Abundance: Oxygen makes up about 46.6% of the Earth's crust by weight.

* Minerals: Oxygen is a major component of most common minerals, such as quartz (SiO2), feldspar (various compositions), and mica (various compositions).

* Rocks: Since minerals are the building blocks of rocks, the high abundance of oxygen in minerals translates to its high abundance in rocks.

While oxygen is the most common element, other elements are also found in solid form within the crust, including:

* Silicon: The second most abundant element at 27.7%

* Aluminum: The third most abundant element at 8.1%

* Iron: The fourth most abundant element at 5%

* Calcium: The fifth most abundant element at 3.6%

These elements, along with smaller amounts of others, combine to form the diverse range of minerals and rocks that make up the Earth's crust.