Bible Dictionaries
Touchstone

Webster's Dictionary

(1):

(n.) Any test or criterion by which the qualities of a thing are tried.

(2):

(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.

Bibliography Information
Webster, Noah. Entry for 'Touchstone'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​t/touchstone.html. 1828.