The thesis work of Albert Yen addresses these issues.
Future spacecraft will address the problem of 'water' on Mars.
Yen is working on instruments which will be able to analyze the water content
of the Martian surface. He is also interpreting existing spacecraft
reflectance data in the 3 micrometer IR region in comparison with laboratory
data of hydrated potential Martian minerals to obtain an estimate for the
amount of water which we can anticipate to find at a future lander site.
These are synthetic phases devoid of any significant impurities. The grain size is about 1 micrometer in each case.