Stain appeared on my 1 week old limestone fireplace!

[Behoove]

Help please. We haven't even moved in yet, the new fireplace (sealed limestone) was fitted last Friday and the remote control for the gas fire was placed on the mantelpiece.
When I moved it today there is a dark mark where the remote was left.

Will it fade? Do I call up and get it fixed, can it be fixed you think?

[StuntCodPiece]

I read your title as Stalin and thought a weird depiction of the infamous dictator had somehow manifested itself in your home.

[Behoove]

That would have been posted in Woo though

But what about my stain

[2plus1]

We are looking at having stone hearth for our new log burning stove. I understand that the stone will go patchy as it dries out over the first month of it being in situ. Is it possible that the remote sitting on the stone has stopped that patch drying out as much as the rest hence the patch/stain that you see. I would see if it fades over the next week.

[Behoove]

2plus

Yes, I just came back on to say the mark disappeared overnight so must have been condensation or similar related, so panic over.

[mymummademelistentoshitmusic]

But if Mother Theresa appears in another place you'll know there's something going on.

[StuntCodPiece]

[PigletJohn]

"there is a dark mark where the remote was left."

this suggests that damp is coming up through the substrate and evaporating off the surface. Where it was covered and could not evaporate, the surface stayed wet.

Is the stone laid on new damp brickwork, or was it outside in the rain before fitting?

[Behoove]

The room is all newly plastered but (we thought) it was entirely dried, maybe still dampness in the room?

Don't know where the stone was stored prior to fitting though.

[PigletJohn]

I don't know how long limestone takes to dry out. It is less porous than brick, so I suppose more than a month per inch of thickness.

If you get fluffy whiskers or crystals appearing on the surface, brush them off, it will be dissolved mineral salts.