Recollections of working stone: part one

By Lorraine Clay

When Anne Mitchell asked me to cover worked stone with Gary Lloyd at the 2022 Ness of Brodgar excavation I went mudstone grey.

Not only did I have little knowledge of worked stone or geology – Gary had written papers and produced videos on worked stone! How could I help? After the initial desire to cry came the desire for knowledge and I pressed Anne and Gary for articles that I could access online and available books.

Visits to bookshops were fruitless. Gary directed me to the Working Stone website and Anne to Anne Clarke’s blog and publications. I read into the night, absorbing every bit of information I could gather, and pestering Gary with every stone – “Is this sandstone?”; “Is this siltstone?”.

Gradually I began to get it right.

As a potter and craft instructor as well as an archaeologist, I realised my way to understand the materials I was looking at was to engage in the making process – to create my own Skaill knives and stone bars. To problem solve during the trial and error involved in their creation.

Beachcombing

The first leg of experiments came out of the assertion that Skaill knives were made by throwing cobbles down onto other fixed stones.

As I intended to take a pilgrimage to Ostara crafts, a visit to Skaill Bay was not far out of the way. Even with sticks I decided going too far down the beach was not good health and safety and focused on picking up cobbles quite high up the beach and throwing them at larger stones.

This caused the thrown cobble to bounce some distance with a loud ring, like a Tibetan bowl, without it breaking.

Several attempts gave no results.

Finally, one stone bounced onto a third and split into three (one half crosswise and two quarters width wise (Figure 1).

Ness geologist Martha Johnson has told me that the split cobble had already been worked, which might explain it being slightly weaker than others tried.

While at the shore, I also collected flag to make stone bars (Figure 2).

Picking a polissoir was limited by my ability to carry one, although a couple caught my eye as having potential to be used in situ (Figure 3) and it seemed feasible the best place to work tool was at the beach or where bedrock provided a firm work-surface.

The rocky shores east and west of the Ness of Brodgar could be a good place to look for polissoirs, anvils, and debitage.

Flaking the stone bars using a hammerstone, “workbench” and direct percussion on the beach resulted in the stone flaking more than desired.

Polishing the resultant bar on the Skaill bay polissoir (Figure 4) was only slightly successful in rounding the jagged edges (Figure 5) but not in creating a useable tool.

Rock art at the Ness

In an attempt to split the thick side of the broken Skaill cobble (Figure 1), I threw the cobble at a sandstone block, left from an open-day display, and discovered that the cobble was leaving  a white peck mark on the sandstone but was itself undamaged.

This immediately told me the sandstone was softer than the cobble and gave me the idea to continue direct pecking the sandstone. Within 15 minutes I had created a cup-mark.

Adding a ring was almost instinctive – following the outside curve of the cup – and this process took about another hour – surprisingly no great time at all (Figure 6).

Using the sharp, fine edge of the Skaill split quarter cobble I incised lines with ease (Figure 7) and rubbed a small piece of clay (from the ground beside the finds hut) and incised lines through to create a contrast, all in a matter of minutes. The rubbed in clay became quickly indistinct.

Chris Gee also donated a piece of haematite to draw red lines,  which also left an indent, remaining after the colour was washed off.

To test how easy it was to create curves and spirals, I drew with a quartz fragment (Figure 8) from Birsay on the fine polissoir and on the sandstone with the quartz pebble – easily creating a white line.

On a flag from the Trench J spoil-heap (thanks Ray) I pecked a shallow horned spiral directly (Fig 9), still using the half cobble (Figure 11), in a matter of minutes.

On the edge it was more difficult to control direct percussion to create eyebrows (figure 10), and the Birsay fragment was too small to hold, so a broken quartz cobble from Scapa was bought into play as a point (Fig 8) and the side of the split cobble used as a hammer (Figure 11).

This was tricky to do on the thin flag, and splitting of the layers began early when the hammer and point was close to the edge. I believe I held it in front of my knees, chocked and with one side on the ground.

Axing a lot!

I was advised by Chris Gee that the best way to fashion a polished stone axe is to start with a stone as near to the shape you want. With this in mind a foray to Scapa beach was successful.

The flat, flared, stone was very similar to an axe to start with so only needed the wide end sharpening.

Using the Skaill Bay polissoir was slow work and I was advised to use a rougher stone, which Chris Gee proffered me from a spoil heap.

Initially I sat in a chair, leaning forward using one hand at a time (like I would with a carborundum), with the stone on the ground, chocked by stones around it to reduce its movement. I progressed to kneeling in front of the stone, still using one hand at a time, so pushing at a slight diagonal (focusing through the shoulder and on the tricep).

Using two hands, separately, created wear across the surface of the stone, rather than a channel, as I felt for points of engagement/friction.

The sandstone was used for sharpening the blade and the Skaill Bay cobble for polishing the blade and the sides (Figure 12).

An initial sharp blade took about seven hours, but letting the public try caused some blunting. So I decided to focus on polishing and to leave the final sharpening for last.

Water or not?

I was advised to use water but sometimes this seemed to decrease abrasion. While it is good health and safety, I wonder whether there is evidence of its use in prehistory. The water and stone dust running down the stone leaves creamy lines and a build-up in recesses, which could be looked for on/around worked stones.

Without water the dust could be brushed/swept off. Water with an abrasive might resolve the lost friction?

To be continued >