Wow, how disappointing. Have you tried to contact the installer. That would be my first step. Have them come out and look. Hopefully they will be able to advise you on what needs to be done.

Hi, I am sorry to hear about your issues. I have been talking with other fabricators about your problems and the consensus (without pictures or more info) is that you do indeed have a sealant problem.

Remember, the stone is as susceptible to absorption from the bottom as it is from the deck. That is why we seal the underside at all undermount sink areas, and pay attention to splashes as well.

When you are referring to the air vent, do you mean the vacuum break in the line?

Sorry to hear about your problem(s). Thanks to Tom for alerting us about your issues.

First of all, sounds like the stone needed/needs to be sealed. The darkening from water is an easy indicator. Water will not harm the stone.....but for a sealer to be effective, the stone must be dried out completely before application. You can let it dry naturally for a couple days, or use a hair dryer to help speed up the drying. In the meantime, be wary of "dark" liquids that could cause an actual stain that would be more difficult to remove.

I would try working with your original fabricator/installer first. If you can not get any help there, post or e-mail me and I could likely recommend a competent person in your area to contact.

Regarding the cracks, I would need to see a photo/pic of the affected area to help determine the cause and a solution.

Have you tried contacting your fabricator ? How long has it been installed ? Sounds like it wasn't sealed or needs to be resealed. But your original fabricator should be able to help you.
Good Luck

Thanks to graniteshop for jumping in here.

Now that I have seen what an air vent is (they are not required in my area), I have a better understandiung of why it may have cracked.

Another fabricator wrote the following:

"The hole for the vent is drilled all the way through the material like a faucet hole and is most likely an 1-3/8" diameter just like the rest of the faucet holes.

There could be a couple causes of the crack. It could have been cracked during the install and not noticed until this point. It's also possible that they crack was caused when the hole was drilled. If they did it on site with the wrong style core bit enough heat could have been built up to cause the stone to crack. Also, if the cabinets were not level or if the top was not properly shimmed the top could crack after install. If the top was cracked before install it will still probably be perfectly flat. If it was cracked after install then you may be able to look down the top and see either a high point or low point in the top at the location of the crack. "

Seems like good info to me.

I want to thank everyone for jumping in. Yes, the air cap is for the dish washer and may have been drilled on-site. I don't recall them sealing anythning at the house. It has been about 6 years since the install and that comapny is gone. I will try and post some pictures. Thanks again everyone, for some reason I do not get an eamil of follow-up messages on Garden Web???

It's called an "air gap". Just another 1 3/8" whole. Required by many states/municipalities, supposedly to make bad things not back up into the dishwasher, or something like that.

I had the tiniest crack on my new granite on the corner of the cooktop. The fabricator was able to come out and make it disappear. Really, you'd never know it was there! (I think workers and/or my husband stood on the counter when messing with the hood).

What I ended up doing was drying out the area and then took a stiff brush to remove any loose dirt and cracking. I then filled using a 3M concrete expoxy (black) and let dry for several days. I then took a fine razor and removed excess expoxy and sealed the whole area. This seems to be working fine and the dark expoxy matches my multi-colored granite pretty good. We will see if this will last.