You may have heard that there is no natural non-toxic sealer for real stone countertops.
I found that natural sealers outperformed synthetic sealers without the VOCs or PFAS.
I tested all of the natural (as well as synthetic sealers here) stone sealers on many different stone types.
The testing went on for many months!
This article contains affiliate links, upon purchase I earn a commission at no extra cost to you.
Summary: My top pick is definitely a walnut oil/wax mix which has long been used successfully on real stone. There are some caveats – there are some stones and some situations where this will not work well.
Walnut Oil Sealer Overview:
Walnut oil is an all-natural food-safe low-odor “drying oil” that works as an effective sealer for real stone and is usually the best choice for most applications.
Drying oils polymerize, forming a durable finish on the surface.
In my experiments Soapstone Sealer worked much better than synthetic sealers, and it’s easier to retouch when you do spill something like vinegar.
(Synthetic sealers can often not be retouched).
It also contains carnauba wax which gives it a very slight sheen and helps with durability.
Because stone countertops do need re-sealing fairly often, this becomes an area of priority to have something low tox.
Stone types
The company recommends this Soapstone Sealer on honed stones (though in my trials it did work on shiny stone as well).
Also there is a very slight yellowing and noticeable darkening so it didn’t work well on white stone and it was iffy on light grey stones.
Marble, granite, soapstone, limestone, and slate can all be sealed with this oil.
I can certainly see why this is sold as “Soapstone Sealer” since it creates a perfect black finish on soapstone.
While mineral oil is the most common sealer for soapstone, it’s not as durable. Walnut oil is better.
Alternatives?
If you have an allergy or aversion to walnut oil, hemp oil is the next natural oil to try.
Hemp oil has more of a hue to it than walnut oil and it can produce a greenish tone on light-colored stones.
For white stone
For white and light colored stone, check out these synthetic sealers.
What didn’t work
Tung oil was too thick (so you can’t retouch it in the future).
Coconut oil doesn’t polymerize so wasn’t durable.
Walnut Sealer Application
The main drawback, once you choose a stone that is color compatible, is probably the time it takes a natural walnut oil finish to cure.
You should wait 5-7 days before using the surface, with a full 15 days before you start scrubbing it and using it to full capacity.
When it comes time to re-seal, simply add the oil in sections so that you can still use part of your countertops, or do it before going on vacation.
If Your Stone is Sealed Already
To tell if the stone is sealed already, do a water test – put a big drop of water on the stone and see if the stone changes color.
If the color does change then it is not sealed.
If it does not change it is likely already sealed.
The walnut oil sealer can seal over an already sealed area.
It’s not going to soak in or be quite as effective, but it will dry and polymerize.
Also, it will need to be kept very thin so as to not build up too thick of a film.
My countertop post goes over stones that are dense enough to not require a sealer.
So if water does not soak in, that can also indicate that it is one of these very dense stones.
If you want to skip the whole sealing stage altogether, go with one of those stones.
A Closer Look At Hemp Oil On Stone
Hemp oil as a stone sealer can work well.
I tried it and it did work in my experiments on stones where it is color-compatible.
Walnut oil is usually the best choice for all stone countertops. The color change is very subtle and it’s easy to re-do and touch up without build-up.
Some may prefer hemp oil. The color change is more than walnut oil but it will show up immediately, as opposed to yellowing over time says Dwayne, the owner of Real Milk Paint.
On stones where I saw a color change to yellow, I did see it right away and it did also worsen a little bit over a few days or weeks.
My Test Results – Comparing Multiple Products On Different Stone Types
You don’t need to read though this section, but if you want to see all of my experiments and the other products I tested they are outlined below.
Products Tested
I started by testing many different oils, waxes, as well as MetaCreme (now called Stain Proof).
I tested walnut oil (with carnauba wax), tung oil, hemp oil, and MetaCreme (now called Stain Proof) on a few different stone types.
I tested dark marble, creme marble, slate, and later – white marble, grey limestone, and dark grey soapstone.
MetaCreme is a synthetic sealer, not a natural oil, but it is marketed as low odor and low-VOC.
This is one alternative to the natural oils for those who are chemically sensitive or avoiding toxins.
I tested two other synthetic low VOC sealers here (especially good for white and light-colored stones).
Oil Versus Water Based Sealers
I found that the “drying oils” – hemp, tung, and walnut all held up well as countertop sealers.
They work best on dark or warm tones stones since they can yellow light-colored stones.
However, thick oils like tung will not work over the long term because a second coat will turn white.
Water Repellency
Walnut oil repelled water perfectly.
After a water test, none of the stones were left with a mark indicating that water had soaked in.
Resistance to Dye and Acid
I then threw mustard at all of them, both for the pigment and for the acidic vinegar in it, and left it on for a few short minutes.
The dark stones were all marred by the vinegar which broke through all of the finishes I tried.
The oil-finished stones were much easier to touch up.
To fix those white spots all it took was adding a little more Soapstone Sealer and right away it looked back to normal.
And because these oils are so safe to work with you can do that yourself with a small rag.
Synthetic stone sealers on the other hand are not easy to touch up after a vinegar spill.
Those white spots were not fixed by adding another coat of Metacreme, so I was not as happy with the results.
I would pick walnut oil as my top choice for most stones, with some exceptions…
Which Stones Will Walnut Oil Seal?
Any honed stone can technically be sealed with walnut oil, though white and light grey-colored stones will have yellowing. I would not recommend this on white stone, it does not look good.
This is the main drawback.
It did work just fine on a creme-colored marble pictured above.
On a light-colored grey limestone, it was ever so slightly yellow. Some people may be OK with that and others might not.
Definitely test this out first if you are going with any light-colored stone including limestone – this might look totally fine or it might alter the color too much.
On really light stones that are white or cool tones, check out these three low-VOC synthetic options.
Make sure to test the products if you are sensitive to chemicals, as you will be resealing the stone every few years or so.
Did the Oils Hold Up To Tougher Stains? (Plus More Oil Comparisons)
Walnut vs. Coconut vs. Jojoba
After I narrowed in on walnut oil as being the best all-around oil out of the first batch, I started another round of testing with lighter stones.
I also wanted to see if refined coconut oil could deliver the same results without any yellow or green color change.
I threw in Jojoba oil since that is a great finish on many natural surfaces like wood.
(It turned out that worked much better on my skin and hair!)
Refined coconut oil is not a “drying oil”.
Unlike walnut, hemp, and tung which polymerize forming a durable coating, coconut oil does not polymerize to form a topical coating.
Using a formula with wax makes it a little more durable and it did succeed in not yellowing any of the stones, but it did not hold up very well when actually put to the test.
And it won’t hold up for as long.
Light Gray, Dark Gray, and White Stones
I tested two very similar samples of limestone that are cool-toned light grey, as well as white marble, slate, and dark grey soapstone.
Pure refined coconut oil can be used on soapstone and other stone counters that don’t truly need a sealer (as well as cutting boards), just keep in mind it does not polymerize to form a durable film.
Results
I put them all to a serious test with palm oil.
Coconut and jojoba certainly failed, with walnut oil offering the most protection.
Palm oil will be one of the hardest substances for natural oils to hold up to since it stains red and it’s an oil which other oils can’t hold up to.
Other Countertops You Can Seal With Natural Oils
- Concrete countertops
- Paperstone
- Wooden countertops – but see this post.
Related Posts:
- Non-Toxic Countertops
- Synthetic Sealers for Stone Countertops (good for white stone)
Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.
Join the top Substack on healing from MCS and mold!
Julie H.
Hi Corinne, thank you for sharing your research. I’m looking into sealing a new slate floor (in an entry way, kitchen and dining room). Would you recommend walnut oil for a floor as well or do you suggest another product? We prefer a matte finish and only want to use a relatively safe and healthy product. Thanks again.
Corinne Segura, Building Biologist
slate doesn’t always need sealing but yes walnut oil can work or synthetic sealers in the book
Cris
What do you recommend for black quartz? Thanks!
Corinne Segura, Building Biologist
quartz doesn’t need a sealer
Cris
Unfortunately, I believe there is a color enhancer on our quartz that wasn’t even applied and left swirl marks – trying to find a more natural stripper than using chemicals if you have any suggestions. Thank you!
Robin Sheingold
Great article! I am making a candle holder from unpolished river rocks but am looking for a non-toxic way to keep excess candle wax from seeping in to the rock and staining it. Any thoughts for what I should use? Stones are generally light grey. Thank you.
Carl
Hello. I found your website when I was looking for a non-toxic wax or oil for wood interior cabinets. I know the article is about stone but could you advise what would be best for untreated wood? Ideally something that doesn’t need to be re-applied every year. Thanks Corinne
Corinne Segura, Building Biologist
hi I have a number of articles on natural oil finishes for wood. If you want it to be super durable like for kitchen cabinets then the best article is the one on natural oils for wood floors
Dawn
hello. Found your article while I was online looking up info on a natural food safe sealer for my marble. We are building a new house, the marble has been installed but is covered right now while painters are painting.
I have honed marble, white with some veining. I am a baker and want to put my dough directly onto the countertop. So I want something safe. I cannot use walnut oil according to your article or it will yellow my white marble.
I read somewhere that you can use olive oil to seal honed marble. you did not mention olive oil in your article so wondering about that?
There are some sealers that claim to be food safe for marble. I like the natural patina look, but I would like some protection on my marble from stains as I have a large island, grandchildren, etc., so it will get a lot of abuse. Thx for info!
ps i also got honed soapstone for the rest of my counters and will put marble behind my oven after vent hood installed.
Corinne Segura, Building Biologist
olive oil is not a drying oil. I address that in the article
Heather
Thank you for all the information. We are planning to install a leathered Bianco Superiore quartzite, which is lighter whites, greys, and some dark veining. It sounds like walnut oil can yellow the slab? Are there any other options? Thank you.
Corinne Segura, Building Biologist
yes you have to go with the synthetic sealers in the article i link to in this one
Mireille
I was ready to seal my quartzite when I started to read the chemical sealants dangers – how it was flammable (my quartzite is in my kitchen), how I could be come dizzy and drowsy, how it can cause severe skin and eye irritations and I thought – either there is something safer out there or my quartzite is just not going to get sealed. Thank you for saving me and my spouse as well as our quartzite!!!!
Jess P
can i use plain walnut oil on a natural stone shower floor, or do I need to use a walnut oil/wax product?
Corinne Segura, Building Biologist
Yes I believe you can just use the oil for darker stones, and give it the full cure time.
Melanie
Hi-
Could you recommend which oil to use for basic speckled granite? Wondering do I just clean it well and then rub it in all over and polish- let it soak in?? Thanks
Corinne Segura
follow the directions from the manufacturer.
Jason Maynard
My wife is 15 yr MCS sufferer. REALLY thankful for your website/work. I noticed you don’t throw Linseed Oil into the stone sealers with the other “drying oils”. Any reason for that? FYI, noticed that BLO dramatically darkened my slate on test and I’m switching to one of the others. Thanks
Corinne
you def don’t want to use BLO as it has additives like metallic driers. Pure linseed might work, I didn’t test it. Walnut oil is likely better as it’s thinner so touch ups are seamless.
Marguerite
Hello – and thank you so much for this thorough research! We are re-sealing an old marble tub and wondered if the walnut oil mix would be effective after preparing the stone. Thank you so much in advance!
Corinne
depends on the color of the marble. White marble will yellow with the walnut oil
Amy
This is so helpful and timely as I am new to granite and have it as my counters in my new kitchen! Quick question: Does granite need to be sealed annually? I know our granite countertops were sealed by the contractors when we moved in a year ago, but we haven’t done anything to them since. Would you recommend applying the Walnut Oil every year? Thank you for this blog!
Corinne
Countertop sealers last around 2-5 years. Sealers break down over time. The resin is degraded by cleaning products and by general use.
Porous stones are more susceptible to stains and will require sealing more often (1-3 years). Check the density and integrity of the past sealant with a simple “water drop test”. Each stone is different, and sealers and quality of application vary – you have to do a water drop test to determine if or when to seal your stone.
Water Drop Test:
Stone must be clean and free of dust
Place a single drop of water (quarter size) on the stone
Length of time to absorb: <1 minute porous; >1 minute non-porous
Perform three tests for the first 2,000 ft2 and at least one for each additional 3,000 ft2
Be sure that you are not using cleaning products that etch the stone and break down the sealants (no vinegar, no hydrogen peroxide, etc), here are non-toxic cleaning and disinfecting products for real stone.
Beth
Wondering about walnut oil for sealing beige color travertine in a shower. walls, floor
Corinne
Yes you can use that, it needs a full cure of 30 days.
TJ
Hi! Thank you for this research! We have a family member with nut anaphylaxis so walnut oil is out for us. Would you suggest hemp oil for granite counter tops? What about travertine showers? Thank you!! (We also have immuno compromised folks who need to soak in the tub so we need the natural route for sure).
Corinne
I mention my experiment with hemp oil on stone in the article.
Erica
What do you suggest for sealing a Quartz countertop?
Corinne
Quartz doesn’t need a sealer
Lauren
Would walnut oil hold up to seal stone tile for a shower floor?
Monica
Can I use walnut oil on a slate floor?
Corinne
Yes, slate might not need a sealer though.
Johannes
I wonder what would happen if you use the walnet+wax mix on a polished surface?
Corinne
I tried it and it seemed fine!
Nikki
Hi!
Thanks for doing all this lovely research! We are about to install honed Mont Blanc Marble and to avoid chemicals we plan to seal the marble with the walnut/wax mix you suggest. Do you know of anyone whose done this to their own kitchen? Would love to see a blog or picture of someone whose out this product on their honed marble from day 1! There’s such little information out there- only running across companies pushing to sell their product.
Corinne
There are photos in this post. It’s going to yellow the white.
Lori Rettig
Would you recommend bees wax or food grade mineral oil, or a combination of the two for granite? Sealing or polishing or both/neither?
Corinne
The walnut oil with wax is my top choice for sure.
Jean
Is Mahoney’s Walnut Oil Wax what you’d consider “walnut oil with wax”? If yes, what area would you expect 8 oz. to cover? If not, where can “walnut oil with wax” be found? Thanks!
Corinne
I link to the one I like and have tested in the post
Deanna Wu
I tried clicking on the link for the walnut oil from the Milk Paint company. It seems as though they don’t sell that product anymore. Do you have any product suggestions? Or can you just use regular food grade walnut oil?
Corinne
They still make it, it seems the link is temporary broken
Chris
Have you tried SimpleCoat? Just wondering if it’s actually nontoxic.
Corinne
It’s 100% proprietary so I really don’t know what that is. If you know someone from the company, they can send me a sample!
Brittany Beck
Hi Corrinne, I am with SimpleCoat and would love to work with you and send you sample. Would you be able to email me at brittany@idgroupbranding.com?
Isabella
Corinne,
Thank you so much for sharing all of this valuable research and knowledge.
Here is a question for you- I made an outdoor fountain from a large standing ceramic pot. The pot is glazed on the outside, but I need to seal the inside which is unglazed porous terra cotta. I want to use a cost effective and environmentally safe sealing product to protect (birds and wildlife). What do you recommend for this application?
Dyer
Hi,
Thank you for this very in depth article – you have certainly done your research and work!!
I have a granite countertop (dark browns, blacks, golds and very little white/grey – I’m also not concerned at all about coloration). I do not know if it was sealed at the factory – I know very little about that. I also don’t know how or even IF it has been sealed by former owner on a regular basis or at all. I DO know it has a lot of “pits” or “cavities” – I presume that means it needs sealer? Not sure if you know the answer to that but my other question is if you think castor oil would work?
I ordered some organic castor oil for something else (and can’t use it) but I saw all these natural oil you mentioned above and wondered if you knew/thought castor oil might be an option.
Thanks!
Corinne
No that is a non-drying oil, I would not use it.
Diane
If you were looking at quartz or quartzite would you choose quartz over quartzite, because of sealing and more care and risk of stains? Quartzite comes in more colors and such but ease of care and also no worry with care, or MCS is important!
Corinne
I prefer natural stone but only if it either doesn’t require a sealer or you can use a natural sealer like the walnut oil (so no light colored stone that isn’t naturally dense).
Laura Toppazzini-Bazan
Thanks so much for this very informative article!
What is the safest counter top (toxic wise)? Do you recommend SILE STONE?
Corinne
Countertops are all listed and reviewed here! https://www.mychemicalfreehouse.net/2019/06/a-non-toxic-kitchen.html