The eight most abundant elements in the Earth's crust make up 98.5% of its composition.

Here's a breakdown of those elements and their approximate percentages:

* Oxygen (O): 46.6%

* Silicon (Si): 27.7%

* Aluminum (Al): 8.1%

* Iron (Fe): 5.0%

* Calcium (Ca): 3.6%

* Sodium (Na): 2.8%

* Potassium (K): 2.6%

* Magnesium (Mg): 2.1%

While these eight elements make up the vast majority of the crust, there are many other trace elements present in smaller amounts.