 Earth 's mass is approximately 5 @.@ 97 × 1024 kg ( 5 @,@ 970 <unk> ) . It is composed mostly of iron ( 32 @.@ 1 % ) , oxygen ( 30 @.@ 1 % ) , silicon ( 15 @.@ 1 % ) , magnesium ( 13 @.@ 9 % ) , sulfur ( 2 @.@ 9 % ) , nickel ( 1 @.@ 8 % ) , calcium ( 1 @.@ 5 % ) , and aluminium ( 1 @.@ 4 % ) , with the remaining 1 @.@ 2 % consisting of trace amounts of other elements . Due to mass segregation , the core region is estimated to be primarily composed of iron ( 88 @.@ 8 % ) , with smaller amounts of nickel ( 5 @.@ 8 % ) , sulfur ( 4 @.@ 5 % ) , and less than 1 % trace elements . 
