A comprehensive metallurgical study of gold coins from the reign of Chandragupta II has revealed that the Gupta Empire achieved a level of gold purity (exceeding 99%) that was virtually unmatched in the ancient world. The research, utilizing X-ray fluorescence, shows that ancient Indian smiths employed a sophisticated cupellation process that utilized specific botanical additives to remove impurities.
This discovery underscores the scientific prowess of the 'Golden Age' of India. The consistency of the gold content across different mints suggests a highly centralized and regulated economic system, reinforcing the historical narrative of the Gupta period as a peak of Sanatan prosperity and technological advancement.