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Reading here:

if the peroxide does seem to help is that the bubbles forming and foaming is helping dislodge tiny particles in the cracks of the mineral.

Is this the case in general for cleaning with hydrogen peroxide, i.e. there is no actual chemcial reaction, its just dislodging particles?

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    $\begingroup$ Whether there is a chemical reaction depends on the sort of dirt on the rock. The article cites some reactions where it is a chemical process even while claiming that the bubbling also does some good. Organic material,a common contaminant of rock samples, is chemically destroyed by peroxide and some mineral stains will be chemically altered by it. The bubbling is likely a bonus physical effect, loosening soil and dirt, and not the primary effect. $\endgroup$
    – matt_black
    Commented Jul 23, 2021 at 14:31

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Well, it is a play of words. Chemical process or a physical process do not mean a lot. Dilute hydrogen peroxide decomposes catalytically by many things, including dust/ grime, plant matter, minerals, iron oxides, etc. When it comes in contact with dirty rocks, it begins to decompose and begins to bubble oxygen. This bubbling action may loosen dirt.

Since geologists test many minerals rocks by acids (dilute hydrochloric acid), bubbling indicates carbonate, which is essentially like decomposing the rock/mineral being tested. The author is trying to point out that when dilute hydrogen peroxide is "acting" on the rocks, it is not chemically decomposing them; rather, it decomposes itself into oxygen and water.

It can certainly cause chemical changes, for example if there is sulfide in the "ore" material, it will be slowly converted into sulfate.

Nothing is inert in this world, including water.

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  • $\begingroup$ I am not a chemist. In my mind, a physical process is as described here, a particle is dislodged. The dirt and the O are not bound whereas a chemical process would be like soap, where one end of the soap molecule binds to the dirt, the other end to water, and the dirt gets carried away as part of the soap molecule. Is this accurate? $\endgroup$ Commented Jul 22, 2021 at 16:10
  • $\begingroup$ Yes, this is correct. Physical cleaning would be akin to blowing air from a dirty surface. It is just mechanical force that "cleans" the surface. $\endgroup$
    – AChem
    Commented Jul 22, 2021 at 18:54

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