noun
touchstone
TUCH-stohn/ˈtʌtʃstəʊn/
A stone used to test precious-metal purity.
The jeweler rubs a gold ring against the touchstone.
Etymology
A touchstone tested gold or silver by comparing the streak rubbed onto it with known samples. This practical test of metal quality became a figurative standard for judging anything's quality.
In context
It's the touchstone of this modern era of fighting, where all things that used to make the sport unusual are mostly gone
More examples
- The gold leaves a thin streak on the touchstone.
- She uses a touchstone to check the purity of the gold.
- The workshop keeps several touchstones beside its other testing tools.
Forms
touchstone · touchstones