It is more or less like the constituents of the Earth soil
The most available substances of Mars soil are
Aluminium oxide
Magnesium oxide
Calcium oxide
Sulfur oxide
Silicon oxide
Nickle
Sodium oxide
Zinc
Iron oxide
The following are some of the Earth soil constituents
Element (Soils(mg/kg Median O 490,000 Si 330,000 Al 71,000 Fe 40,000 C 20,000 Ca 15,000 Mg 5,000 K 14,000 Na 5,000 Mn 1,000 Zn 90 Mo 1.2 Ni 50 Cu 30 N 2,000 P 800 S 700