English: Incomplete coarse greisen saddle quern with a worn concave central reservoir, and one remaining built up edge, through use as a quern or grain mortar. The other edges of the quern have been lost and this may be because the stone was dressed in more recent times in order to re-use it for building material. Similar to other saddle querns found around the county on Bronze Age sites, such as Trethellan, Newquay, where several varied examples were found, the closest in form illustrated in Nowakowski (1991) on pages 144 & 146, Figs.59-60, Nos.92 & 94 from the Middle Bronze Age round house 2001, and a quern derived from a hornfels surface slab with quartz crystals surviving from siltstone, providing 'bite', from the Late Bronze Age contexts at Scarcewater, St Stephens, illustrated in Jones and Taylor (2010) on page 129, Fig.66, No.509.

The greisen probably derives from the nearby outcrop which flanks the granite at Tregonning Hill in Breage. The greisen is coarse with mica flakes of up to 4 mm across and larger quartz grains up to 10 mm across which are particularly prominent where the white mica has eroded out. Greisen is a metasomatically altered granite where the felspar has disappeared and been replaced by white mica, which is also soft. The difference in hardness between the quartz and the mica means that the stone maintains a good grinding surface without becoming smooth. Greisen is also relatively easily shaped, so it was often used for quern production (Dr Roger Taylor pers comm).