The Earth’s Crust

The Earth’s crust is made up of various elements, but they are not all present in equal amounts. Studies of crustal composition show that oxygen is the most abundant element in terms of percentage by mass.

Oxygen combines easily with other elements to form oxides, silicates, and carbonates, which make up the majority of rocks and minerals.

Most common minerals in the crust—such as quartz (SiO₂), feldspars, micas, and clays—contain large amounts of oxygen.

About 90% of the crust is made up of silicate minerals, all of which have oxygen in their structure.

Approximate Composition of Earth’s Crust (by mass):

Oxygen – ~46.6%

Silicon – ~27.7%

Aluminium – ~8.2%

Iron – ~5.0%

This clearly shows that Oxygen is nearly half of the crust's mass.