I agree. They don't want to because it will cost the supplier and the contractor money. You could agree, in writing signed by all parties, that if the polishing on-site does not yield a satisfactory result, then it is to be removed and reinstalled promptly. Withhold payment until it is worked out. Good luck.

Thank you. I'm going to try that. I called several marble fabricators today who all told me that polishing on site will never look the same as if it was installed polished.

That's a new one. I've only heard of the other way around.

I have the same issue now. The supplier sent out honed herringbone backsplash instead of polished. It was installed and I don't like it. Can it be polished while on the wall? Will it look good?
Thanks in advance.

Update: I had my contractor rip the honed backsplash from the wall and replace it with the polished. I don't think DIY polishing a honed marble will ever work and ever look as a store bought polished marble mosaic. So, I opted with replacing the whole backsplash. Worth it!

As a contractor I can honestly say that if both installer and supplier have admitted to making the mistake they should be allowed to try and satisfy your requirements. All natural stone can be polished but how well it is done is another story. If you are not happy with the end result of polishing the tile have them replace it and at their cost.

Any great contractor should do what is necessary to provide 100% customer satisfaction. All the best!