Touchstone
Esquema
Jerarquía
<materials by composition> > inorganic material > rock > sedimentary rock > <sedimentary rock by composition> > chert > flint (rock)
Descripción
A velvety-black variety of cryptocrystalline quartz, siliceous shale, or similar substance used by jewelers for testing the purity of precious metal, especially gold, by the streak left on the stone when rubbed with the metal.
URI original del concepto
Otros términos
- 試金石 [zh]
- toetssteen [nl]
- pierre de touche [fr]
- piedra de toque [es]
- shì jīn shí [zh]
- shi jin shi [zh]
- shih chin shih [zh]
- basanite [en]
- Lydian stone [en]
- stone, Lydian [en]
- pierre d'essai [fr]