Highland Border Slate was sourced from numerous quarries located within a narrow swathe of ground extending from the island of Bute in Buteshire to the town of Dunkeld in Perthshire. In the past, some of the slate now included in this building stone was known by the name of the local area from which it was sourced (e.g. Aberfoyle Slate, Dunkeld Slate). The stone consisted originally of mud that was deposited on a sea floor during the Neoproterozoic Era (c. 600 million years ago), when Scotland was south of the Equator at roughly the same latitude as Patagonia is today. Metamorphism during the Caledonian Orogeny (c. 470 million years ago) produced a planar metamorphic fabric in the stone, along which it now splits readily. Highland Border Slate was used locally and regionally, mainly for roofing but also for masonry. Highland Border Slate is not quarried for building stone today.

Building Stone ID 10,104