Koidu diamond mines
코이두 다이아몬드 광산
The diamond country of Kono District in eastern Sierra Leone: an open pit cut into kimberlite pipes, and alluvial diggings along the rivers. During the 1991-2002 civil war rebel groups financed themselves with diamonds from this region, the origin of the term "conflict" or "blood" diamonds; the Kimberley Process certification scheme followed in 2003.
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- Country
- Sierra Leone
- Type
- Infrastructure
Quick answers
Where is Koidu diamond mines?
Koidu diamond mines is in Sierra Leone.
Koidu is a diamond-mining city in the Kono District of Sierra Leone, West Africa. About 128,000 people lived there at the 2015 census, making it the fifth-largest city in the country. It is a centre of the diamond trade, and two of the world's ten largest rough diamonds were found in the Woyie River that flows through it.
The best known is the Star of Sierra Leone, a 968.9-carat diamond found in 1972 in the Koidu area. Today the Koidu Kimberlite Project mines diamonds from two small rock pipes in a lease of about 4.9 square kilometres. Diamond mining here shapes the town's work and trade.
The Star of Sierra Leone
On 14 February 1972 miners in the Koidu area found a stone weighing 968.9 carats. It is the fourth-largest gem-quality diamond known and the largest alluvial diamond ever found, meaning it came from sand and gravel in a river area. The New York jeweller Harry Winston bought it, and it was cut into 17 finished diamonds, 13 of them flawless. The largest was a pear-shaped stone of nearly 54 carats.
Mining today
The Koidu Kimberlite Project lies in the Tankoro Chiefdom. Its two small kimberlite pipes, K1 and K2, are rock columns formed deep underground that hold diamonds. After the civil war ended in 2002, Koidu Limited was the first company to invest in commercial diamond mining there. Mining began in 2003 and created a very deep vertical pit near the town.
Fun facts
- Two of the ten largest rough diamonds ever found came from the Woyie River near Koidu.
- The Star of Sierra Leone was cut into 17 diamonds.
- The Star of Sierra Leone was found on 14 February 1972.
On the globe
The toy globe marks the diamond mine at Koidu in eastern Sierra Leone. Zoom in to look for the open pit.
Nearby on the globe
Sources
Updated: 2026-10-14