Minerals
Minerals are natural resources needed as raw material for setup and extension of settlements on Mars. From recent unmanned missions some valuable minerals have been found in the regolith, most of them by the Mössbauer spectrometer MIMOS II. The atmospheric dust contains minerals, which allows atmospheric mining. The crust is enriched in iron. It is rich in chlorine, sulphur, potassium and phosphorus (as well as other volatile elements).
The most common elements making up Mars' crust are: silicon, oxygen, iron, magnesium, aluminum, calcium, & potassium. The elements sulphur, phosphorus, sodium, boron, chlorine are needed for life and have been found on the planet.
Overview:
Goethite
Chemical formula: α-FeO(OH)
This mineral has been identified near the landing zones of the rovers Spirit and Opportunity, for example at "Columbia Hills". This mineral was probably created from iron under the influence of liquid water.
Hematite
Chemical formula: α-Fe2O3
This mineral has been found at the landing zone of Opportunity. It is also suspected to be very common over the entire martian surface. Hematite is an iron ore, a source of Iron on Earth and should be on Mars as well.
Olivine
Chemical formula: (Mg,Fe)2SiO4
This mineral has been found in Gusev Crater.
Salt
Calcium carbonate, magnesium, sodium, potassium, chloride and perchlorate have been found by the Phoenix lander (http://phoenix.lpl.arizona.edu/09_09_pr.php). Chloride, perhaps table salt, have also been found by Mars Odyssey.[1]