The eight most common elements in the Earth's crust, in order of abundance, are:

1. Oxygen (O)

2. Silicon (Si)

3. Aluminum (Al)

4. Iron (Fe)

5. Calcium (Ca)

6. Sodium (Na)

7. Potassium (K)

8. Magnesium (Mg)

These elements make up over 98% of the Earth's crust by weight!