The grout color selected should have matched the limestone and not contrast it.

Thank you for your answer.

The installer suggested a contrasting color to highlight the pattern....

I'm not unhappy with the grout color though. It looks lighter in person and also in another areas were the grout has dried better.

What bothers me are the stains in the surface of the material and I'm trying to find a way of fixing it and figuring out why it has happened (characteristic of the material or mistake in not pre-sealing the tiles).

Natural stone will absorb the moisture in thin set and grout and change colors. It will dry out and change back. Until you take your first shower. Limestone is extremely porous and there is nothing that you can do that will keep it from absorbing moisture and changing colors. Seakers only slow down staining. They do not eliminate it. Your designer should have told you the minuses as well as the pluses of working with limestone.

Andressa, didn't you have an appearance you were trying to create for the room? Here is limestone on a wall and a floor.

They usually fill the holes with a matching color. Limestone is a very soft stone isn't it? I love it. Had it in my kitchen and it etched terribly from acids. Get the right cleaner for it. It's so cool!!!

Thank you all for your comments and advices. You are great!

I'll be talking to the installer tomorrow to check the solutions he offers and I'm also in contact with the store were we purchased the tiles. When I have more info I'll get back here to let you know.

Follow some better pictures, so you can see the difference of the tile before and after grout, which for me looks huge:

Wrong materials. Wrong grout. Wrong expectations.

i now have the exact same problem. what did you end up doing? did anything work??

Me too!

Me too! Would love to know what solution was ultimately used.

Same here. Had a 160 sqft wall full of White Oak Honed. Selected darker grout to elevate the appearance. (Material https://www.msisurfaces.com/products/natural-stone-collections/marble/white-oak/). I did not know, neither did the installer that the stone absorbs grout. After grouting a few tiles, he alerted me to the issue. Called the manufacturer. They suggested that we seal it and then grout. Installer sealed 1 coat and applied grout over the entire wall. Despite it, the grout destroyed the entire wall. Installer blamed cheap store.

I also bought enough stone for a 2 story 4 side fireplace in the middle of the room. This time, I had him apply 3 coats of seal and then grout. It came out perfect. Stone did not absorb grout.

But every time I look at the 160 sqft wall, I cringe. Gives me a sick feeling in my stomach. Been an year now. I like Tileworks LLC's response. Hire a stone restoration company to refinish. Just setting aside some $$ so I can call a stone restoration company.

Lessons learn't the hard way.

Here is the wall. U will notice the stains. The tile is much brighter

Once grout is filled in all the holes and indentations you can't really remove it but you can use a grout colorant to stain it to a color to lighten it.. wipe it on the grout will absorb it and wa lag you will have a much lighter color..