India was the only place where diamonds were mined. Early references to diamonds in India come from Sanskrit texts. Kautilya’s Arthshastra mentions the diamond trade in India.
Buddhist works dating from the 4th century BC describe the diamond as a well-known and precious stone but do not mention the details of diamond cutting. Another Indian description written at the beginning of the 3rd century describes strength, regularity, brilliance, ability to scratch metals, and good refractive properties as the desirable qualities of a diamond.
During those times Calcutta was an important trading centre for diamonds in central India.
Diamonds were traded to the east and west of India and were recognized by various cultures for their gemological or industrial uses. In his work Naturalis Historia, the writer Pliny the Elder referred to the Adamas (invulnerable stone) that occurred alongside gold and was used for ornament.
This was long believed to refer to diamond but is now thought more likely to mean other hard minerals such as Corundum & Spinel. Diamonds eventually spread throughout the world, even though India had remained the only major source of the gemstone until diamonds were discovered in Brazil in 1725.
A-Chinese work from the 3rd century BC mentions: “Foreigners wear it [diamond] in the belief that it can ward off evil influences”. The Chinese, who did not find diamonds in their country, initially did not use diamond. As a jewel but used it as a “Jade cutting knife” Diamonds reached ancient Rome from India. Diamonds were also discovered in 700 in Borneo and were used by the traders of southeast Asia.