Removing Rust Stains on Granite

removing rust from granite

Rust Stains on Granite

It doesn’t happen often, but certain colors of granite can rust. The image attached is an extreme example, but depending on the exposure, some granite (and other stone types) can rust when exposed to moisture.

I recently received a call from NY regarding a recent rust stain appearing on a grey granite. Granite being a natural stone is composed of many different minerals, and iron may be one of them. Untreated (non-resin sealed) granite is more likely to exhibit rust staining than resin-sealed granite. However, even resin-sealed slabs and tiles can rust if not properly protected using a quality stone impregnator.

Before you go to the hardware store and pick up a rust remover, you should understand that many rust removers are acid-based products, and it is vitally important that you test your ‘granite’ to make sure it will not be damaged by acid.

You may know that granite is a quartz and feldspar based stone and is acid-resistant, while marble, travertine, onyx and other stones may be largely calcium-based stone and acid-sensitive, and may be burned or etched.

Test in an inconspicuous area by applying the acid to the surface. If it immediately begins to fizz or bubble, you have an acid sensitive stone and you must remove the product immediately and flush with water. If the rust remover does not react with the stone, leave it sitting on the surface for 15 minutes, then wipe off, rinse and allow to dry. Observe if there is any noticeable change to the finish or color. If not, you may proceed to apply it directly to the rust stain. Follow the directions and dilution rate for your product and rinse.

Once the rust has been removed, it is important to immediately protect the area to prevent the rust from reappearing. When using acids, you are actually oxidizing the area and dissolving the rust. If not sealed, the freshly oxidized area will quickly rust again, and perhaps even worse than before. Sealing the stone (once clean and dry) will retard or even prevent rust from reoccurring. I suggest using a penetrating impregnator, not a topical sealer (acrylics).

HMK R77 Rust Remover

HMK R77 Rust Remover

HMK R77 Rust Remover is a Professional Grade Rust Remover for Natural Stone. Careful observance of directions is highly recommended.

R77 will remove rust stains from Granite, Bluestone, Fieldstone and other cast and natural stone surfaces. R77 may be used on both polished and textured stone. R77 is for acid resistant stone only.

Once area is clean, it is highly suggested that you treat the area with a quality stone sealer to prevent the return of rust.

 

S31 Stone Sealer

S31 Stone Sealer

 

HMK S31 is a Professional Grade Silane Impregnator. S31 is great for all natural stone but if your granite is in a kitchen application we suggest using HMK S34 Silicone Impregnator which has extra grease and oil protection properties for kitchen countertops.

About Torin Dixon

StoneCareOnline Expert Blog is managed by Torin Dixon who is an expert in natural stone importing, distribution, fabrication, installation and maintenance of all natural stone surfaces regardless of finish or texture. We are here to assist you in your StoneCare needs.
This entry was posted in Cleaning Stone, Restoring Stone, Stain Removal and tagged . Bookmark the permalink.

8 Responses to Removing Rust Stains on Granite

  1. Michael Sutherland says:

    I had giallo ornamental granite installed 6 months ago. It showing patchy orange discolouration in high use areas, by the sink and island. The granite has been sealed on a couple of occasions. I am perplexed by the cause and how to remove the discolouration/staining.

    Thanks,

    • Torin Dixon says:

      Michael,
      It sounds as if your sealer is not working, and the moisture is reacting with existing iron oxides inherent in the stone. You may need to use something like HMK R77 Rust Remover, then protect from recurring using a quality solvent impregnator like HMK S34 Silicone Impregnator. These are professional grade stone care products available at stonecareonline.org
      Best wishes,
      Torin

  2. GANGA says:

    Hi, first it was oily and then white patches formed at junction on granite floor.may i know the reason? please help me to remove those oily and white patches?

  3. Tommy Furlow says:

    I am being given a 4′ x 4′ x 2″ granite slab with a steel frame that makes it into a patio table. I have three questions:
    1. I am going to have to move this about 1100 miles in a U Haul trailer. Should I move it standing up or laying down, and will moving blankets be sufficient protection?
    2. It has a small rust stain from a steel can being left on it out in the weather. How do I remove this stain?
    3. The granite has been polished, but the finish has dulled over the years. How do I get the luster back?

    Any answers you can provide will be appreciated.

    Tommy

    • Torin Dixon says:

      Tommy,
      All slab stone should always be moved on edge.
      To answer question #2, first I need to ask you about question #3. Are you sure it is granite, because granite doesn’t normally lose luster like marble does.
      Rust can be removed using R77 rust remover, but cannot be used on marble because it is an acid cleaner.
      It is best to determine if the stone is a granite or marble.
      If you are still interested, you can email a picture at torin@stonecareonline.com
      Sorry for the delay, my notifications are not working.
      Torin

  4. Phyllis Wilso says:

    I had Granite installed about 4 months ago. The bar (counter) area, if you look at it
    from one side it has a nice shine, from the other side it has a dull finish look. Is this
    something that can be rectified?

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