Oxygen is the element that is found in both biotite mica and muscovite mica and makes up the greatest percent by volume of earths crust.
The most common chemical elements that are found in the earth's crust includes; Oxygen-46.6%, silicon-27.7%, aluminium- 8.1%, Iron - 5.0%, calcium- 3.6%, etc. This is evident that oxygen is the greatest chemical element in the earth's crust.
The chemical element oxygen is also found in minerals biotite mica and muscovite mica. The major difference is that Biotite contains elements iron and magnesium while muscovite does not.
