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Rainbow Stain on granite around sink

Posted by facgge (My Page) on
Wed, Apr 22, 09 at 20:56

Just curious if anyone has seen or heard of this. We have Impala Blue granite that was sealed upon installation 2 1/2 years ago. Our 4 windows go right down to the countertop, so we have a lot of natural light in our kitchen - which we love, except.... when it comes to keeping the countertops clean - EVERYTHING shows during the day (not as much at night) and I find the granite very unforgiving and hard to keep clean and streak free. Unfortunately we do have hard water, and any water that does dry on the counters ends up leaving a white stain. Luckily those stains do dissapear once they are wiped down with water and dried with a towel. I try very very very hard to constantly wipe down the water that gets splashed on the granite around the sink, but with 3 boys.....you know how that goes!!

My question is whether or not anyone has experienced a "rainbow" stain, which I have all around my sink. Funny, you only see it during the daylight and only when the sun does NOT shine directly on the granite. I called my fabricator last summer who came out to my house to see the granite, but had never heard or seen this problem. He was thinking that maybe it was even from the plumber when they installed the faucet because the biggest stain is right at the base of the faucet. After researching and coming up with nothing, he gave me a number of a stone doctor - but I have yet to call him, hoping someone here might be able to give my some insight. The only thing I can think of is that water is somehow trapped in the granite and giving that rainbow effect. Blue Impala has a very low absorption rate (.05-.15), and one that I didn't think needed to be sealed every year. When they came out last summer he said that it should absolutely be sealed every 6 months - but they do seal everything. If I were to leave a wet sponge on the counter for 10 minutes - it does not leave a dark spot and I have never had a problem with oil stains.

However, I also have a lot of small dark rings on my granite, especially above my dishwasher. I have a seam above my dishwasher and they had to come back 6 months after installation and repolish the stone about 1 foot on either side of the seam because during the day, you could see that this area on either side of the seam was much lighter than the rest. I imagine that these rings too are water stains, but after a year, I would think that it would finally dry up. So perhaps I do need to seal this stone - but wanted to find out if I can remove this rainbow stain and dark circles before I do.


You may be wondering why I have waited so long to get this fixed....I had a few issues with the installation - the area around the seam for one (because of course I was being way too picky and had to call them out a few times...) and I was furious when they never asked what reveal I wanted and assumed that I would want the negative reveal (which the overhang is way too much and I lose valuable sink space in the smaller sink of my double sink) even though I gave them the Franke template that calls for a positive reveal....Bottom line though, I never knew that I should be the one to ask or tell so I blame myself for not researching that (clearly I found GW way too late!) I have had some other issues with my kitchen too, which are a bit embarrassing so although I have read thousands and thousands of entries, I have never had the nerve to answer one or ask a question.

But today is a new day! I am so sorry I have made this much longer than I did and I am hoping that I have made some sense. Any insight at all would be just great.

Thanks!


Follow-Up Postings:

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RE: Rainbow Stain on granite around sink

I hope someone has the answer to this on, because I have the same rainbow phenomenon on the granite in my bathroom.


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RE: Rainbow Stain on granite around sink

Anyone?


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RE: Rainbow Stain on granite around sink

When we were installing our Silgranit sink I read here in the forum that the plumbers putty is oil based and will stain the sinks. Because you say it's especially noticable around the faucet, I'm just wondering if your plumber used that putty to seal the faucet and sink maybe?


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RE: Rainbow Stain on granite around sink

I was hoping we'd get the stone gurus to answer! I also have the "rainbow" around my faucets & SDs...bit it's also along the top of the sink area.


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RE: Rainbow Stain on granite around sink

The only thing I can think of is that water is somehow trapped in the granite and giving that rainbow effect. Blue Impala has a very low absorption rate (.05-.15), and one that I didn't think needed to be sealed every year. When they came out last summer he said that it should absolutely be sealed every 6 months

You're right, and your stone guy's wrong. That stone does NOT need to be sealed. I'm wondering if oils from plumber's putty might be causing the rainbow stain. As for the rings above the dishwasher, My questions would be if that were from glasses or what have you, why only above the dishwasher? I'm wondering if it my be some kind of inclusion in the stone that the heat from the dishwasher may be activating and that would be why it's only showing in that one area.

I'm going to ping stonegirl and have her take a look at this, as well. Between her and Kevin, maybe we can get to the bottom of this.


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RE: Rainbow Stain on granite around sink

Thanks Bill! I actually pinged not just you, but also Kevin, StoneGirl, & Paulines!

I also have the rainbow effect...but only around the sinks (all the sinks...main, prep, PR!) So it seems you may be correct as it must be something all 3 have in common.

Is there anything we can do about it?

I have "AB Premium" (the name our stoneyard had for it). I know it doesn't need to be sealed...


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RE: Rainbow Stain on granite around sink

Yup..Like I said, probably plumbers putty!


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RE: Rainbow Stain on granite around sink

Here's my thoughts (and for wiw, I noticed some rainbow spots shortly after my own stone install), I think it's due to superficial absorbsion of some type of oil based material - not necessarily limited to plumber's putty.

Fabricating shops utilize oil for their machines and stuff and I think some can be transfered to the material (even oil on hands). This oil gets sealed under the polish (so to speak) giving a rainbow type effect.

The good news is that with a soft machine buff (done by a pro, pleeze), the spots go away!

Thanks for thinking of me Buehl, hope all is well with you.


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RE: Rainbow Stain on granite around sink

That takes care of the rainbow, stain. I'm still curious about the rings above the dishwasher.


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RE: Rainbow Stain on granite around sink

The rainbows could also be due to minerals like iron in the water. A careful scrape with a sharp razor blade would most likely also take care of them.

Is there any way you could post a picture of the rings above your dishwasher. Without looking at them any opinion would be a mere guess.


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RE: Rainbow Stain on granite around sink

Thanks all! So if I want to get rid of the rainbow I need to find someone to come in to do the buffing...the fabricators who did my counters are no longer affiliated w/EXPO (what's left of it) or HD...too many complaints about them! I'm not sure I want them anywhere near my counters again anyway.


It's nice to see some of the "old timers" back! I remember all the help you used to give us Paulines & StoneGirl! We also have Kevin, Bill, and Joshua to help, but it's nice to hear from the ladies as well!


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RE: Rainbow Stain on granite around sink

My new KA dishwasher came with a shiny silver, adhesive-backed plastic vapor/thermal barrier that is to be placed on the underside of a laminate countertop (above the DW) to protect the wood underlayment from heat/steam. If it should turn out that the dishwasher's heat and moisture is causing the rings on your granite, perhaps something like this could help.


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RE: Rainbow Stain on granite around sink

I have absolute black and the stains are only where the faucet drips. I have hard water and a water softener and I am wondering if any of you have water softeners because I am suspecting it is the salt???


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RE: Rainbow Stain on granite around sink

We have the same rainbow effect on our black granite coutertops. They appear only around the sink area, which leads me to beleive it's from soap and water.

I am going to try buffing and polishing and will report back to the group.

If anyone has tried this or anything else and had success/failure, please share your feedback.

Thanks!


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RE: Rainbow Stain on granite around sink

I have the same problem with my Black Galaxy, it's 3 years old and I have never sealed it. What is the best thing to buy to seal it with?


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RE: Rainbow Stain on granite around sink

I have absolute black granite, from different remodels and different stoneyards, in two bathrooms and in the kitchen.

Over time, all of the absolute black counters have developed rainbow stains (like the ones in the picture attached) around the sink areas, or wherever water gets splashed from the sink. It seems to be particularly bad near the soap dispenser, so I suspect it has something to do with soap as well.

Has *anyone* had any luck getting rid of these? If so, pleas help - they are definitely spreading!

This thread is the only resource on the web on this issue, so if someone has a solution it will probably help a lot of people. Thanks!


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RE: Rainbow Stain on granite around sink

Can You send some other photos.
I have never seen black ab get photographed so blue.


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RE: Rainbow Stain on granite around sink

It's difficult to get the rainbow effect, since it appears on the right lighting conditions. Trying to attach more photos.


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RE: Rainbow Stain on granite around sink

Here's a slightly adjusted photo. You'll see the rainbow stain on the edge.


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RE: Rainbow Stain on granite around sink

Under the stain the areas looks abraded. What is that darker mark off to the left?
Anyway have you tried to clean it with a degreaser? or anything else.
Black absolute is a very dense material so the stain should be sitting on the surface.
Lets try the path of least resistance.(wear gloves)
Protect your floor and countertops using some plastic sheeting. Try using a strong degreaser which is high alkaline. Klenzall from DuPont or an aqua mix product from home depot or a tile shop may work. Try cleaning one area with that and see what you get(you will need to rinse). You can also try-
Try and clean off one area with denatured alcohol. Wear Gloves and be mindful it is flammable so take the proper precautions.
Let us know the results.


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RE: Rainbow Stain on granite around sink

I have been struggling with this issue around the sink area for a few months now and watching it get worse. It looked exactly like the photo posted by 'gardeno17' and was also on Black Galaxy. I have tried Thinners, Acetone, Sugar Soap, Lemon Juice, Bleach, etc. No difference whatsoever.
Yesterday I found some 'Brasso' metal polish wadding in my cupboard and tried it. It has totally removed the discolouration. Its trade name is Duraglit in the UK and it is commonly available with cleaning products. Its active ingredient is listed as Aliphatic hydrocarbon (which I think is similar to parafin). It does seem to have dulled the surface ever so slightly (not noticeable unless you are looking for it) but if you decide to give it a try do a small area first. I'm not sure how or if my granite was sealed, though I understand this one shouldnt be sealed, but for me - the Brasso has worked!


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RE: Rainbow Stain on granite around sink

"Fabricating shops utilize oil for their machines and stuff and I think some can be transfered to the material (even oil on hands)." - this is possible but HIGHLY unlikely.

I am a fabricator and an engineer that worked for a stone machinery manufacturer before starting my shop. Of course stone working machinery has oil and grease in somew locations. However, the basic design of those machines normally precludes any contamination of the product (stone)

From comments which include references to hard water and removal by an abrasive pad it sounds to me like surface hard water deposits which are common in my service area. Several times a year we do a service call for a "stain" only to find it's merely hard water residue that is easily removed with steel wool.

The other possibility I suspect due to the "rainbow" is an oil or soap stain which can normally be removed with a hydrogen peroxide poultice.

my 2 cents


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