On the excursion during the Sachsensymposium in Trondheim last month we visited Slipsteinsberget (“Grindstone Hill”). Not only did we visit the place, but the entire conference (some of whose participants were in their 70s) climbed around the whole hill (rain-sodden, wooded and steep) like mountain goats. Our guide was the charming Bodil Østerås, head of Egge Museum. Her 2002 Augmented Master’s Thesis (No. hovedoppgave) Slipsteinsberget i Sparbu : kva eit klebersteinsbrot kan fortelje om gamle steinhoggartradisjonar deals mainly with the site we visited.
The hill consists mainly of soapstone, talcum and serpentine. Indeed, there is no mineral in it that is actually useful for grindstones. So then, why the name? Probably because an entire hillside untouched by later quarries is covered by curious circular scars where people have obviously extracted stone. There are also mine tunnels whose insides are covered with the scars. They look like they may have something to do with wheel-shaped grindstones. But in fact, they’re from Late Iron Age and Medieval soapstone pot production.
Soapstone pots are ubiquitous on Norwegian Viking Period settlement sites and coeval sites elsewhere connected to Norway by trade. The material (which is partly talcum) is soft enough to be carved with woodworking tools, and it has excellent thermal properties. To make a pot, a stone carver would carve a pot-sized little dome out of the hillside and then lop the dome off before hollowing its inside out. This left a characteristic round scar. There are also a few surfaces with rectangular scarring where building stone has probably been taken. Much of the hillside is hidden by enormous spoil dumps from the quarrying, so there is most likely much evidence for how the work was done to be found underneath. Bodil has trial-trenched a house foundation on top of a dump and got a 15th-century radiocarbon date.
Update 6 October: Dear Reader Brian points out that there’s a remarkably similar 1st Millennium soapstone vessel quarry in Newfoundland, belonging to the Dorset Culture.