QUESTION:
Do you think any important minerals will be discovered on Mars?  
 
ANSWER from Ted Roush on July 7, 1997:
To a geologist all minerals are important because they provide clues to
how the surface formed and changed over time.  For example, igneous 
minerals would suggest that volcanic activity has occured on Mars, 
sedimentary minerals would provide evidence for the action of wind or 
water on Mars, and metamorphic minerals would provide information 
regarding the activity of the interior of Mars.

Studies of meteorites believed to come from Mars have not identified any
minerals different than those we already know about from Earth.  When we
return samples from Mars it will probably be similar to early 
exploration of the moon when the Apollo astronauts brought back lunar 
rocks.  The vast majority of the minerals identified in the lunar rocks 
were the same as minerals on the Earth with only a handful of 
exceptions, so we might see a few new minerals from Mars, but probably
not many.