This si a comment on Houzz

If you google "full color thermal bluestone" you'll see many examples of this (and unfortunately other mislabeled examples of non-thermaled and other types of bluestone, but if you open the links and look specifically at the thermaled full color you'll see examples). - As a natural stone the layers during stone formation can make it look this way. If you had a piece to see from the side you'd see it goes through the stone.

Thank you, Patricia. I’m not sure I understand what you’re saying in regard to my stone?

Did you begin by Googling your issue?

https://www.sealersplus.com.au/cleaning-sealing-bluestone/

As BLUESTONE weathers, the colours can show changes to brown or rust-red due to oxidation into rust of its iron-rich minerals. Sealing BLUESTONE with Professional Grade sealers is recommended to offer for stain resistance and make ongoing maintenance easier.

Have you called the installer?

Thank you, Beverly. Yes, I Googled but didn’t see that particular quote. Can you share the source? Would love to see if there are photos attached. (If not, I’ll just Google the exact quote.) My installer recommended against sealing so we didn’t. I’m more curious why this one area is so much worse than others, could there be moisture seeping in here? Is that a factor?

I did share the link

I see, thank you

It is your stone mentioned and if you look at the edge of the stone you will see the brown in it I think is what the quote is saying.

Thank you, Patricia. Ours is Blue Select Bluestone, which is supposed to only have shades of blue. It’s more expensive than Full Color Bluestone, which is also beautiful, but is not the look we are going for. My issue is that my Blue Select now looks more like Full Color.

Sure. Was it sealed?

No, installer recommended against it

It is not "discoloration" .I doubt sealing would have made a difference and is not necessary .

From below:

"However, true blue stone may still, over time, display other colors as minerals in the stone are exposed to the environment."

........................

“True Blue” bluestone refers to stone that does not exhibit any other colors except blue when removed from a quarry.

Veins of true blue are rarer than full color – also called variegated – where imbedded minerals create the waves of green, brown, and lilac colors mixed in with the blue. True blue flagstone consequently costs more than full color. However, true blue stone may still, over time, display other colors as minerals in the stone are exposed to the environment.

AND............

Another part of bluestone’s appeal is that is easy to take care of. It doesn’t require sealing and is cleaned with only water and a brush.

If your bluestone is stained, just add some vinegar and water to the surface and scrub it out, although you can purchase specialty cleaners for unusual or severe stains.

The only other maintenance recommendation is a power washing once every few years. Bluestone owners should take care not to power wash on the highest level as the stone can be grooved by intense water pressure. Bluestone is one of the easiest surfaces for homeowners to maintain.

Would you like to learn more about Pennsylvania Bluestone? Contact Woodward Landscape Supply. Better still, visit us in person to see this marvelous, durable stone for yourself."

Hi Shannon - how’s it looking now? My bluestone (full range) is looking dull and brown in front of the house. The back looks good. I suspect it’s because the installer used muriatic acid on the front and not the back. I’m looking for a way to bring back the color - is yours still looking good after the acid wash? Thank you!

Hello! It could be oxidation of iron deposits in the stone. Our contractor is currently treating our bluestone to remove efflorescence and salts that were causing stone flaking- it removed the brown and rust colors from our “blueer” thermal bluestone.

Melissa, can you please share what your contractor treated it with? im struggling with both issues you described - flaking and brown. I want my beautiful blue back.

There is so much conflicting info on how to treat bluestone - acid/no acid; pressure wash/no pressure; seal/no seal. Thanks!