When we install your Stone fireplaces we wash the fireplace down after installation to remove any dust or dirt on the stone. The stone darkens in colour when wet but lightens once the stone has dried out. It can take up to 2 weeks for the stone to completely dry out.
Here’s our Haycombe Bath stone fireplace which we installed a week ago. This photo was taken the day after we installed the surround, as you can see the stone is a lot darker due to it being very wet, the main photo shows the fireplace a week later. You can see it’s starting to dry out but probably has another week to go until it’s fully fried out.