Hello. Thank you for your question and interest in our work. On this project we designed the shelves on the right and the buffet cabinets on the left as linear elements that visually connect from one side of the space to the other. The center section, fireplace, interrupts these lines and is extended vertically. The bottom most element visually extends from one end to the other, past the fireplace and becomes the outer hearth. For this section under the fireplace, we used Indiana limestone. It is revealed off the floor in alignment with the shelves and buffet cabinet plinth - thanks for noticing that detail. Thanks again.

Thank you for your response...it's details like these that make the difference...I'm always on the look out for them.

Fireplace: Are you saying that the grey tile is limestone??

Hello. Thank you for your question and interest in our work. Not sure we completely understand your question, but we'll try to provide some information. The hearth is Indiana limestone. This is the large, cut stone below the fireplace. The stone on the wall is a charcoal slate, which is a different topic than the original question. Hope this helps, and thanks again for the question.