a mineralogic model , derived from computer mixing studies and laboratory analog preparations , suggests that mars fines could be an intimate mixture of about 80 percent iron-rich clay , about 10 percent magnesium sulfate ( kieserite ? ) , about 5 percent carbonate ( calcite ) , and about 5 percent iron oxides ( hematite , magnetite , maghemite , goethite ? ) .
C0302583
iron
C0060240
iron oxides