Frank Szmulowicz, Ph. D. Dec 21, 2014:

@kamilw: You are clearly right that there are rocks of hydrothermal origin:
Hydrothermal mineral deposit, any concentration of metallic minerals formed by the precipitation of solids from hot mineral-laden water (hydrothermal solution). The solutions are thought to arise in most cases from the action of deeply circulating water heated by magma. Other sources of heating that may be involved include energy released by radioactive decay or by faulting of the Earth’s crust.

kamilw Dec 21, 2014:

@MacroJanus: I guess "hydrothermal" indicates the origin of the dust/particles as they come from hydrothermal rocks, but correct me if I'm wrong. Need more context. Those particles can be suspended in air as well.

Jacek Konopka Dec 21, 2014:

@ Literary- Wydaje mi się, ze ma Pan/i absolutną rację- z dust chyba nic nie wyjdzie, chodzi to o inny sens. Macro Janus chyba jest najbliżej ('part. matter'- przy czym matter wydaje się istotne). Mogę się mylić.

Frank Szmulowicz, Ph. D. Dec 21, 2014:

@literary: Are these in air or in water? Hydro would indicate water.

kamilw Dec 21, 2014:

Dust / particles of hydrothermal rocks?
http://www.cliffsnotes.com/sciences/geology/metamorphic-rock...

"The focus of this study is on potential lander/rover measurements of weathered volcanic tephra and hydrothermal rocks because these samples resulted from processes that may have occurred on Mars. Fine-grained particles from these sources may be responsible for origination of the dust/soil on Mars that is shaping the planet’s surface character."
http://www.lpi.usra.edu/meetings/marsmiss99/pdf/2523.pdf