Our favorite sales person has a huge piece of white marble on her desk which is stained with all manner of common household fluids. Every single contract is signed on that piece of marble so the customer cannot say "BUT SOMEONE SHOULD HAVE TOLD ME !!!!"

Thanks. Yes my place has this too. I'm going with granite it's held up well.

Couple of questions. Was the marble honed? Was the marbled sealed (e.g., with something like DuPont StoneTech BulletProof Sealer)?

It is polished marble. I did not apply any extra sealer to it.

Thanks for the clarification. BTW - Marble regardless of finish is porous and should be sealed. Wish I'd obtained a large enough sample to replicate your experiment with my honed & sealed marble.

After the first round, I decided just to focus on the nasty 4, which didn't take a lot of space. I had thought about sealing it first, but didn't see that in the comments I had read elsewhere.

I'm so impressed with the rather scientific way you went about this.

Sealant is not armour. While the sealers mentioned are excellent, all they give you is more time to wipe up a stain. No sealant claims to prevent staining.

Funky, it actually was a lot of fun. Especially rummaging thru the kitchen looking for potential nasties!

http://petchhouse.blogspot.com/2006/03/sealing-marble-acid-test.html

This test is what convinced me of the need to seal. Very similar to what you did.

mdln, I agree that sealing is necessary. My concern with the marble was not staining, but etching. It looks to me that the petchhouse post has etching at the end of the experiment. I can tell you there was substantial roughness (etching) from the acidic liquids in my sample. Guess I could seal it and try again.

Thanks golfergirl, but did not mean for you to redo your study, just wanted to see if I could apply your results to my situation. Listed the petchouse link just as a FYI in case you'd not seen it. Yes, if etching is your main concern marble is probably not for you.

Interesting test, I like it!

But, your quartzite is therefore not quartzite, as the results showed. It's most likely dolomitic marble. Real quartzite won't etch at all. However this does show the difference in the etching between the two different types of marble.

Your granite sample looks more like quartz than granite. Hard to tell with the tape on it but I'm pretty sure that's not granite.

But your method is very smart, and thank you for taking the time to document and share your results.

Thanks for weighing in, Karin! Can you clarify for me--what difference would sealing the slab make on either staining or etching, if any? We just looked at a slab that is probably dolomitic marble and are seriously considering it because we could live with the results we had.

Sealing doesn't do much for etching, but it does help with staining.

My understanding is that sealer gets down in between the pores and basically fills in those tiny spaces, making it harder for liquids to get down in there. When a sealer is applied, it's wiped off the surface, so you don't really end up with a coating on top of your stone. So the minerals at the surface are still vulnerable to being attacked by acids, which is the cause of etching.

Given your scientific methodology, we'd all love to see the results of a sealed/unsealed staining and etching test on your dolomitic marble. That just might earn you the Nobel Prize in kitchen geology.

Karin, you just motivated me to do that. Next couple of days!

The "quartzite" that you tested looks like super white, which is notoriously mislabeled as quartzite in many stone yards when it is more like marble. You should test on something like Taj Mahal, sea pearl or white Macaubus, which are true quartzite and see what the results are.

My sealed Taj M quartzite has seen a lot (messy cook here). The only situation which gave me pause was a blue ink stain from a glass bottom coated with the ink. Probably sat there two hours before anyone thought to remove the glass from the mudroom counter. A little barkeeper lifted it up where soap sponge failed. Hooray. Love the stuff. Still running my hands across the surface two years in...

Love your test!
Maybe I missed it, but what about staining? I think I could live with etching, but staining is a different story.....
Probably etching would bother me less than those dots on marble-look alike quartz.

Listen, do you hear that? That's Corian laughing at all those stains.

Joseph - LOL - maybe my Cambria is laughing as well - but there are sure some pretty natural stones out there. I might even get tempted for our bathroom.

Golfer - great job on testing the stones. I think this should become a "sticky"

I know this is a really old thread but wanted to comment in regard to @Joseph Corlett, yes granite stains, but the granite is laughing at the scratches on the Corian. I'm considering going with laminate. Seems it is really hard to find a good all-around countertop as it relates to durability.

Very helpful- glad this came up in my search. off to do research with my little sample.

Salonva, it was fun to do. Good luck on your own research!

Here's an article that guides you through various tests. And I agree it is fun!

https://usenaturalstone.org/how-to-be-your-own-stone-sleuth/