What precious elements are found on the surface of mars?
Just as metals and precious materials have been used on earth successfully. Mars materials can be used to further study mars, aide in designing better robots for mars, use those precious materials to explore mars possibilities. Everything about mars comes from those precious elements. If there is life it will incorporate those elements in its life. Make better rovers than can mine those materials and use it.
Plan to explore the basic properties of the elements on mars. Even better discover new elements. Send this data back to earth to study them and answer questions about future missions. Save alot of money if this is successful. And could be the start of new exploration on mars.