A stone sundial is a sundial in which the dial or its supporting pedestal is made of stone. The most familiar form is the garden sundial, a carved stone baluster or column topped by a horizontal dial plate, usually of brass or bronze, with a projecting gnomon whose shadow indicates the hour. Other types include vertical dials carved into the walls of churches and houses and elaborate multi-faceted stone dials.
Sundials were essential timekeepers before mechanical clocks became common and remained useful for setting clocks well into the nineteenth century. In British gardens stone sundials have been fashionable since the seventeenth century, when Scottish masons produced remarkable lectern and obelisk dials with many faces. Georgian and Victorian examples often stand on classical or twisted balusters, and the dial plates are frequently engraved with mottoes, dates, the maker's name and the latitude for which they were made. Collectors check that the plate and pedestal belong together, that the gnomon is original and undamaged, and that the stone is sound. When positioning a sundial, it must be set level and aligned to true north to tell the time accurately.
