[1] : The Collaborative International Dictionary of English v.0.48

touchstone \touch"stone`\, n.
   1. min. lydian stone; basanite; -- so called because used
      to test the purity of gold and silver by the streak which
      is left upon the stone when it is rubbed by the metal. see
      basanite.
      1913 webster

   2. fig.: any test or criterion by which the qualities of a
      thing are tried. --hooker.
      1913 webster

            the foregoing doctrine affords us also a touchstone
            for the trial of spirits.             --south.
      1913 webster

   irish touchstone min., basalt, the stone which composes
      the giant's causeway.
      1913 webster
see also:
basanite irish touchstone 

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Touchstone, definition of term: Touchstone
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Irish Gaelic, definition of term: Irish Gaelic
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Irish Moss, definition of term: Irish Moss
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