Submitted by sudosudoku t3_11ggnrk in askscience
Is martian ground made up of the same minerals and whatnot that you'd find in a desert on earth? Are the rocks found on Titan the same as a cold part of the earth? If they're different, how different are they?
PlaidBastard t1_jarlw8t wrote
Many rock types are fundamentally the same -- basalt on the Moon, Earth. Venus, and Mars is all pyroxene, olivine, and plagioclase feldspar. It weathers into different minerals depending on the environmental conditions, so Martian sand is going to be different from Earth sand (unless you pick a weird place on Earth) in some subtle ways, but it's ultimately a pile of little pieces of the same minerals, just with some textural differences and maybe different trace minerals mixed with it.
Earth also has a lot of life and water. You won't find soil in any recognizable form except here. That's a mix of rotting plant matter and what we call regolith, or the powder to gravel sized pulverized rock that all solid planets have some form of at the surface.
So, you'd encounter familiar minerals and rocks making up texturally odd usually super dry sediments in weird contexts, to summarize.