SHOAD-STONE, noun A small ston, smooth, of a dark liver color with a shade of purple. Shoad-stoners are loose masses found at the entrances 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 massess; they usually contain mundic, or marcastic matter, and a portion of the ore of the mine.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI