Emily Dickinson Lexicon

SHOAD'-STONE, n.

A small stone, smooth, of a dark liver color with a shade of purple. Shoad-stones are loose masses found at the entrance of mines, sometimes running in a straight line from the surface to a vein of ore. They appear to be broken from the strata or larger masses; they usually contain mundic or marcasitic matter, and a portion of the ore of the mine.