01 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 …
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1.
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.(Min.) See: Basanite
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2.
Any test or criterion by which the qualities of a thing are tried.“The foregoing doctrine affords us also a touchstone for the trial of spirits.” — South.
Phrases & compounds
Irish touchstone —
basalt, the stone which composes the Giant's Causeway.