quoted in 2022, C. F. G. Clark, The Curiosities of Dudley and the Black Country […] yet this stone [Cannock] is so Sulphurious and Terrestrial, not fit to make Iron; because the Iron thereof is very Redshare, which is that if a workman should Draw or Forge out a Share mould fit for a Plough in that red heat, it would crack and not be fit for the Use of the Husbandman's Plough or Share.
Source: wiktionary