Fragment of greenstone quern, perhaps dolerite or epidiorite, triangular in plan and semi-circular in profile and in section. Probably a fragment of the lower stone of a rotary quern which acted as a base below the upper stone of similar circumference, linked by a central hole. The two stones were held together by a wooden spindle through the two holes. The upper stone was rotated over the base and grain placed between the stones so that it was ground. The greenstone is typical of that found in the west of Cornwall from known outcrops and contains pale felspars and dark pyroxene inclusions (Dr. Jens Andersen pers comm). The felspars are soft and are worked or weathered into hollows, while the pyroxene is a silicate mineral and therefore hard and stands proud of the surface, creating a shearing action to cut the grain. This fragment is similar to others found on Iron Age and Romano-British sites in Cornwall. Ashbee (1996) illustrates similar examples from Halangy Down, St. Mary's, Isles of Scilly on page 110, Fig.54, Nos.3 & 4, which are dated from the Iron Age to the Romano-Scillonian period. Quinnell (2004) illustrates a similar example from Trethurgy on page 150, Fig.75, No.50, which dates from the Romano-British period.