Shoad-Stone, a term applied to certain loose masses of a fossil, which is generally found at the entrance of mines.

Shoad-stones serve as useful guides to miners, in digging for ores; because, if these minerals, be very ponderous, it may with certainty be concluded that they contain antimony, or some other metal. Being principally found in Cornwall and Derbyshire, it is probable, from the large portion of marcasitic particles in shoad-stones, that Mundic may thence be advantageously extracted.