How did ancient people test the purity of gold? They used a touchstone
Touchstones identify the authenticity and purity of gold -Article source Baidu Baike Touchstone is a solid black stone with a streak of gold on it to show the purity of the gold. The mineralogical name is Bi Xuanite, also known as flint slate, siliceous slate, etc. It is a basaltic extrusive rock, dense, hard, and […]
