The most abundant element in the Earth's crust is oxygen. Making up about 46% of the Earth's crust by weight, oxygen primarily exists in silicate and oxide minerals. These minerals include quartz, feldspar, and mica, found in various rock types. Oxygen's high abundance is critical to terrestrial life, as it is a fundamental component of water and organic compounds. Additionally, it plays a significant role in geological processes like weathering and the formation of soils. This element's abundance showcases Earth's diverse geological make-up and contributes to our planet's ability to sustain life.