Mars is known as the red planet, and the association with the metal makes sense insofar as the reddish-looking surface of the planet indicates the presence of iron in the form of iron (III) oxide dust with the consistency of talcum powder.

Planetary symbol for Mars, alchemical symbol for MarsIron is one of the seven planetary metals to each of which the alchemists assigned the influence of a planet. It is supposedly dominated by Mars, and Karl Wilhelm Scheele (1742-1786), who in his work borrowed some of the system of alchemy, used the planetary symbol to identify iron. The Mars Reconnaissance Orbiter (MRO) was launched with the intention that once in orbit around Mars, various instruments on the MRO will convey detailed observations of the Martian surface, subsurface and atmosphere.

Images on Flickr
Mars Rotate (True Color)
Amazon Books
Image of Destination: Mars (Destination (HarperCollins Publishers Paperback))
Author: Seymour Simon
Publisher: HarperCollins (2004)
Binding: Paperback, 32 pages