Agree the colour blend
Request current material photographs and a sample arrangement. Review the balance of warm, grey and darker pieces rather than selecting from this archive image alone.

STONE SELECTION / PRODUCT REFERENCE
Irregular slate pieces combine warm yellow-brown, muted grey and darker tones. This archived arrangement is a reference for discussing a freeform wall pattern and colour blend.
Confirm current material photographs, dimensions and finish for your project.
FROM REFERENCE TO SPECIFICATION
Request current material photographs and a sample arrangement. Review the balance of warm, grey and darker pieces rather than selecting from this archive image alone.
Provide the wall area, elevations, openings and returns. Discuss piece-size range, joint width and how perimeter cuts will meet corners.
Agree thickness, substrate, setting materials and grout with the installer. Include allowances for site cuts and future replacement.