St Davids 3 is a fragmentary shaft of inscribed metadolerite. It is located in the lapidarium Porth y T'r, St Davids Cathedral (NPRN 306). It was first noted standing in the west bay of the south aisle, adjacent to the font. By 185 it was in the north transept. And by 1949 at the west end of the north aisle. It was moved to the basement in 1994, before being moved to its current location in 2000.

The nearest source of metadolerite is Carn Meini in the Preseli Hills, some 40km away. Dimensions are given as 79cm height max. x 51cm width x 46cm max. diameter. The stone is the lower portion of a quadrangular-section shaft ? probably originally part of a larger cross. It has been remodelled into a cylindrical shape for use as a holy-water stoup or font. It is carved on both faces but the carving is fragmentary and very worn. Face A has a fragmentary roman-letter inscription, incised in six horizontal lines. Face C is carved in relief with fragmentary plaitwork. The carving is thought to be 9th- to 11th-century in date.

Sources include:
Edwards, N. 2007, Corpus of Early Medieval Inscribed Stones and Stone Sculpture in Wales

N Vousden, 26 October 2018