1. touchstone - Noun
2. Touchstone - Proper noun
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.
Any test or criterion by which the qualities of a thing are tried.
Source: Webster's dictionaryThe ultimate touchstone of constitutionality is the Constitution itself and not what we have said about it. Felix Frankfurter
Intelligent investment is more a matter of mental approach than it is of technique. A sound mental approach toward stock fluctuations is the touchstone of all successful investment under present-day conditions. Benjamin Graham
By 'socialism' I mean a classless society in which the State has disappeared, production is cooperative, and no man has political or economic power over another. The touchstone would be the extent to which each individual could develop his own talents and personality. Dwight Macdonald
The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as poetry. Bertrand Russell
Adversity is the touchstone of virtue. English Proverb
Adversity is the touchstone of friendship. French Proverb