Delft Tiles. The blue and white tiles around the fireplace are rendered with wallpaper, but real tiles would have been made of fired clay. Delft, a type of tin-glazed earthenware pottery produced in the Netherlands, was very popular in the American colonies and the royal governors found ways around the British Navigation Acts to allow trade with the Netherlands to continue. By the 18th century, Britian was producing its own blue and white pottery, but the Dutch had been trading in Delftware with the American colonies since the 17th century..
An interesting history of Delft tiles can be found on the website of the Victoria and Albert Museum:
https://www.vam.ac.uk/articles/delftware-tiles
An article about trade with the Dutch in the American colonies can be found here:
https://pookandpook.com/a-delft-touch-in-colonial-america/
Colonial Williamsburg has collaborated with Benjamin Moore to create historic paints for in-home use. This fireplace looks quite similar to the panelled fireplace painted in Apollo Blue on the landing page for the historic paints found here:
https://www.brand.colonialwilliamsburg.org/benjamin-moore
This post is not sponsored, but purely for educational purposes. I lived near Colonial Williamsburg for five years some time ago and gained an appreciation for all things eighteenth century from their extensive collection.