Zinc.
About 7% of the earths crust
The percentage of Earth's crust is less than one percentage in terms of Earth's volume. The Earth's crust is actually a thin layer.
its the percentage in mass !
6%
iron and magnesium
5.4%
Oxygen and silicon
With a very sizable iron core and a (by comparison) wafer-thin crust, I doubt that the earth's crust even approximates a full percentage point.
90 persent and lava
In terms of weight, iron makes up approximately 5% of the earths crust, the fourth most abundant element in the crust. However, remember Earth's Core is nearly all Iron.
The earths crust is a part of the outermost layer.