Burnt and broken portion of a flint knife from Clacharie, Lauder, Berwickshire

Plano-convex knife with semi-invasive retouch, from Airhouse, Oxton, Channelkirk, Berwickshire

Plano-convex knife/end scraper combination tool of flint, from Torlin chambered cairn, Arran, North Ayrshire

Edge-polished knife of flint, from Tormore Cists, Tormore chambered cairn, Arran, North Ayrshire

Edge-polished knife of flint, from Tormore Cists, Tormore chambered cairn, Arran, North Ayrshire

Calcined leaf-shaped plano-convex knife, from Blackhammer chambered cairn, Rousay, Orkney, Early Neolithic

Plano-convex knife of silicified sandstone, from Taversoe Tuick chambered cairn, Rousay, Orkney, Early Neolithic

Plano-convex knife of flint, from Taversoe Tuick chambered cairn, Rousay, Orkney, Early Neolithic

Plano-convex knife of pale grey flint, flaked all over dorsal surface, from Cairnholy chambered cairn No.1, Kirkmabreck, Dumfries and Galloway, Early Bronze Age

Plano-convex knife of pale grey flint, from Achnacreebeag chambered cairn, Benderloch, Argyll and Bute, Bronze Age