A small geological outcrop at the south end of the isle of Iona is the source of a rare stone known since the time of St. Colum Cille and treasured for centuries. Iona greenstone (also called Iona marble, nephrite, jade, and a host of other more-or-less mineralogically correct names) may be found on the beach at Port a Churaich or St. Columba’s Bay. The green and white stone is reputed to be a charm against shipwreck, fire, and miscarriage, and local children collected and sold specimens to the tourists flocking to the island since the eighteenth century. Smaller, sea-polished pebbles have long been referred to as St. Columba’s Tears. During the Middle Ages, a large slab of the material was carved for an altar in Iona Abbey. Iona marble was also briefly quarried nearby by the failed Argyll Quarry Company in the nineteenth century. Iona greenstone was particularly prized for use in jewellery during the Victorian and Edwardian eras.