For most of recorded history, India was the only known source of diamonds. The most famous of its deposits were the alluvial mines along the Krishna River in the Deccan, whose stones were traded through the fortress city of Golconda near modern Hyderabad. "Golconda" became a byword for great wealth, and the name is still used for diamonds of exceptional purity. Stones such as the Koh-i-Noor, the Hope and the Regent are traditionally linked to these mines.
India as the ancient source
Diamonds were known in India well over 2,000 years ago. Sanskrit texts, including the Arthashastra, a treatise on statecraft traditionally dated to the last centuries BCE, describe diamonds and how to judge them. Indian diamonds reached the Mediterranean through trade routes, and Roman writers such as Pliny the Elder mention them. Until diamonds were found in Brazil in the 1720s, almost every diamond in the world came from India. The page on the history of the diamond trade follows how these stones moved west.
India had several diamond regions, including areas in central India around Panna and in the east. The Krishna River valley in what is now Andhra Pradesh and Telangana was the most productive and the most famous.
The Krishna River mines
The Golconda mines were not one mine. They were a series of alluvial workings spread along the Krishna and its tributaries, where diamonds had been washed out of ancient source rocks and concentrated in gravels. Some deposits lay in old conglomerates that had themselves formed from even older river sediments. The ultimate source pipes are still debated by geologists. The diamond geology page explains how alluvial deposits form.
Miners dug pits into the gravel, sometimes several meters deep, and hauled the material up in baskets. Workers then spread it out on prepared floors, washed it with water, let it dry and searched through it by hand for diamonds. Accounts from the 17th century describe very large workforces, including men, women and children, at the busiest sites.
Kollur
Kollur, on the south bank of the Krishna, is the best-known of the Golconda mines. In the mid-17th century it was one of the most active diamond workings in India. Several of history's largest diamonds are traditionally attributed to Kollur, though records are often incomplete. Other named mines in the region included Ramallakota and sites further along the river.
Golconda fort and the diamond market
Golconda was a fortress city just west of Hyderabad. It was the capital of the Qutb Shahi dynasty, which ruled the Golconda Sultanate from the early 16th century until the Mughal emperor Aurangzeb captured the fort in 1687. The diamonds were not mined at the fort itself. Golconda was where they were sorted, valued, taxed and sold.
The sultans claimed the largest stones for themselves, and local merchants and brokers handled the trade in the rest. Foreign buyers came from Persia, Europe and other parts of Asia. The Indian setting of these stones in jewelry is covered in jewelry of India.
Tavernier's travels
The best-known European account of the Golconda mines comes from Jean-Baptiste Tavernier, a French gem merchant who made six voyages to the East between the 1630s and 1660s. He visited Kollur and other mines, observed the work, and bought large diamonds for sale in Europe, including to King Louis XIV.
Tavernier published his travels in 1676. His book describes mining methods, trading customs and the way merchants inspected stones, and it remains an important historical source. Tavernier sold Louis XIV a large blue diamond, often called the Tavernier Blue, which was recut into the French Blue. Most historians accept that the Hope diamond was cut from the French Blue after it was stolen during the French Revolution.
What makes a Golconda diamond
In the trade, "Golconda" refers to diamonds of exceptional clarity and transparency, the kind associated with the old Indian mines. Many of these stones belong to the rare category called Type IIa, which contain little or no nitrogen. Without nitrogen, a diamond can appear exceptionally colorless and limpid, a quality sometimes described as looking like "still water."
Today the term is applied by some dealers and auction houses to Type IIa stones with this appearance, whatever their actual origin. Grading labs can test whether a diamond is Type IIa, but they cannot prove that an old stone came from the Krishna valley unless documented history supports it. Diamond types are explained on the page on diamond chemistry and formation.
Famous diamonds linked to Golconda
Many historic diamonds are traditionally said to come from the Golconda mines:
- The Koh-i-Noor, now in the British Crown Jewels. Its early history is uncertain, and it passed through Mughal, Persian, Afghan and Sikh hands before the British took it in 1849 and shipped it to Britain in 1850.
- The Hope, a deep blue diamond now in the Smithsonian's National Museum of Natural History, cut from the French Blue. Its color comes from boron; see fancy colored diamonds.
- The Regent, found around 1700, bought by Thomas Pitt and sold to the French regent, now in the Louvre.
- The Dresden Green, a natural green diamond held in Dresden.
- The Orlov, set in the Imperial Sceptre of Russia.
- The Idol's Eye and the Darya-i-Noor, a large pink diamond in the Iranian crown jewels.
The stories attached to some of these stones grew over time, and for several of them the exact mine is uncertain.
Decline of the mines
By the 18th century the richest gravels had been worked out. The supply of large stones dwindled, and Brazil's discoveries from the 1720s took over the world market (see diamond mines of Brazil). The Krishna valley mines faded, and later attempts to revive them produced little. Large-scale diamond mining in India since then has been centered on Panna in Madhya Pradesh. The old mining towns left behind ruins and the legend of the Golconda name.
Frequently asked questions
Where were the Golconda diamond mines?
They were alluvial workings along the Krishna River and its tributaries in southeastern India. Golconda itself, near Hyderabad, was the fortress city where the stones were traded.
What is a Golconda diamond?
Historically it meant a diamond from these Indian mines. Today the trade often uses the term for Type IIa diamonds with exceptional transparency, whatever their origin.
Did the Hope diamond come from Golconda?
The Hope is traditionally linked to the Indian mines. It was cut from the French Blue, which Tavernier brought from India and sold to Louis XIV.
Who was Tavernier?
Jean-Baptiste Tavernier was a 17th-century French gem merchant who visited the Indian diamond mines and wrote a detailed account of them, published in 1676.