Summary for hcl on marble Discussion
The thread centers on whether an inhibited HCl solution could remove pink manganese-carbonate stains from marble that is basically dolomite, and whether it would damage the stone. Dave Wichern advises starting with simple lab tests first: check whether HCl actually removes the stains on the specific grade of marble and whether it causes any immediate visible damage before assuming it is safe. In a later update, Heidi Daxberger reports that some marble and chalk samples from the same source did not fizz with 10% HCl, though powdered samples sometimes did. She wonders whether a more dolomite-rich composition and magnesium content could explain the weak reaction. The discussion suggests that the lack of fizz may be tied to the stone’s composition and surface condition, but no definitive answer is given about stain removal or long-term effects.
Q. Hi, I would like to know if inhibited HCl solution could help to remove pink stains of Manganese carbonate from marble surfaces? Our marble material is basically dolomite. Will this solution damage our material?
Thanks!
Rafael Derradi
Industrial Chemistry – Parana/Brazil
January 18, 2022
A. Hi Rafael. Step 2 is probably to research whether HCl is expected to have long-term deleterious effects on marble … and maybe a reader can help you with that.
But step 1 in cases like this is probably some simple labs tests to see whether HCl does in fact remove those pink stains from your grade of marble, and without immediate obvious damage. Please try to give us the results of some simple lab tests before we launch flights of fancy :-)
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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January 2022
⇩ Similar, related, Q&As — oldest first ⇩
Q. I am a Geologist and I teach at a university in Toronto. When we did our rock ID labs the last couple of weeks I was a bit amazed because multiple of our chalk samples as well a marble samples do not fizz with HCl. The samples for each rock type came form the same sources.
Is it possible that it is the same as with dolomite, that they won’t fizz due to bearing some Magnesium as well? We tried to make a powder in one small section but even that did not fizz.
I am puzzled, as were my students and the lab tech.
Thanks for your help in advance
Heidi
Heidi Daxberger
– Toronto, Canada
October 2, 2015
A. Only two things I can think of:
1) Blackboard chalk is calcium sulphate, not carbonate. It won’t fizz.
2) There’s a kind of “marble” that isn’t metamorphized limestone at all, but is some form of serpentine. That’s a silicate mineral and it won’t fizz either.
Real limestone, calcite, marble, etc. are all CaCO3 and ought to release CO2 when exposed to HCl. Is the acid strong enough? Try 10%.
Dave Wichern
Consultant – The Bronx, New York
October 6, 2015
October 27, 2015
Q. Sorry for the delay.
We had some marble as well as some chalk samples in our collection (which we use for the rock ID classes), and these are supposedly form the same source as the others (and the look the same) and they do not fizz.
The acid in our lab is 10% HCl, so it should be fine.
I will try a bit stronger acid next time. And I also will try it with a powdered version of each.
We had some marble on a field trip this weekend, that did only fizz in powdered state. Maybe these samples are more dolomite rich and the Mg interfered with the reaction? Would that make any sense?
Thanks for your comment Dave! Any help with this is much appreciated.
Heidi
Heidi Daxberger [returning]
– Toronto, Canada