Touchstone
(n.) 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.
(n.) Any test or criterion by which the qualities of a thing are tried.
Similar Words:
Cartouch Cartouches Polatouche Retouch Retoucher Touch Touch-box Touch-me-not Touch-needle Touch-paper