We have a "mark" on our Black Galaxy Granite. What can I do?

[HendersonMC]

We have a kitchen countertop made of Blaxy Galaxy granite that we love, but there is a 1"x3" mark on the surface that we do not have a clue as to what we did to cause. (We were told that granite was harder than everything else we had and we did not need to work about scratches, abrasions, etc. as long as we did not drag granite or diamonds over the surface...)

Can somone give us a clue as to what we could have done that caused the mark and how to get rid of it?

[Mark D.]

Henderson MC,
Are these scratches or is this a discoloration? The statement you made is fairly accurate, but water will mark granite given enough time....look at the Grand Canyon.
Did you use Scrubby pads to clean it? They are made of silicon carbide and they will eventually mark granite, but these look like scratches from the pic.
Can you feel them?
Describe this to me in better detail so I can advise you on whether to fill them and re polish, stain the area, or maybe they are a chemical that has gotten into your stone that you need to flush out of it.
I will look for your replay.

Mark

[HendersonMC]

When viewed closely, it seems more like general roughness. Like, perhaps something acidic had removed the less dense portions of the granite.  The surface feels smooth with the lightest pressure, but with somewhat more pressure, feels less slick than the unmarred surface. You cannot detect the scrach groves with you fingers.

We have tried various stone polish solutions that is applied, allowed to dry, and then buffed with a towel. They have made no difference to the rough area, although they do improve the gloss of the unaffected areas. I cannot determine if these contain anything that would abrade granite; (the ingrediantes were a hydrocarbon, wax, and PE copolymer) We have also tried pot scrubbers (yellow (teflon safe), then green (not safe)) to no effect to either the smooth or rough areas.

[Mark D.]

You probably hit the nail on the head when you said "perhaps something acidic had removed the less dense portions of the granite". It doesn't take much on unsealed granite. If you lay a lemon slice on the granite for 5 minutes it will remove the polish and start etching the stone. You can fix this though. It is up to a 3 part process. Remove sealer, wax or oils, stain to match darker stone, and if necessary re polish. Let's go through this step by step:

1) remove sealer, wax, oil, etc...look back in posts. You need to use a solution of caustic soda and water to suck out any sealers, waxes or other stuff from the stone. I think your stone is unsealed, but you said in an earlier post that you had tried waxes so this is a necessary step. After removing sealer & stuff from stone rinse thoroughly with water and allow to dry.

2) Let's stain the stone black to match the rest of the granite with Pectro from Tenax. Here is the link:
http://www.defusco.com/tenax-pectro-black-stone-treatment-liter-p-2303.html
Apply this with a cloth just like a wood stain. After a few minutes it will dry to a haze. Buff with extra fine steel wool. Try it first only on the affected area, but you may decide to redo the whole counter. When you buff it with the extra fine steel wool it will shine to a gloss. If the gloss is where you want it to be then you are finished. If not we will go to step three.

3) Let's re polish the affected area with Diaglo from Abrasive Technology. This powder has very fine diamond grit, and is easy to use. Sprinkle where you want a higher gloss, then mist over with water. Buff it with a felt pad on a grinder at low RPM . The powder and water mix to form a paste and as the paste dries mist it with water as necessary . You may have to do more than one application to get the gloss to match the rest of the slab. For this procedure you need:
a variable speed grinder (not a 10,000 rpm grinder),
a backing pad with a Velcro face,
a felt wheel with a Velcro back and
Diaglo for dark granite.
Here are all 4 links (the grinder would only be $159.90 without the 2 diamond blades):
http://www.defusco.com/bosch-angle-grinder-diamond-blades-p-1360.html
http://www.defusco.com/rigid-backing-pad-velcro-p-1940.html
http://www.defusco.com/alpha-felt-wheel-velcro-back-p-2360.html
http://www.defusco.com/diaglo-dark-granite-1qt-p-1453.html

As long as the finish of the granite is not rough with deep scratches in it this process will cure what ails you. When you are finished I highly recommend taking the 20 minutes to seal your counter to prevent this from happening again (plus it will stain Proof your stone). Try this:
http://www.defusco.com/tenax-impregnator-and-sealer-liter-p-2095.html

If you have any questions please call me Monday through Friday at 800-289-6834.

Glad I could help,
Mark