Definitions Found:
A piece of fine-grained dark schist or jasper formerly used for testing alloys of gold by observing the color of the mark that they made on it
- touchstoneA piece of fine-grained dark schist or jasper formerly used for testing alloys of gold by observing the color of the mark that they made on it
- touchstonesA piece of fine-grained dark schist or jasper formerly used for testing alloys of gold by observing the color of the mark that they made on it