In the district of Ratnapura there are more than 200 working gem mines. The mines are around 100 ft (30 m) deep, each with a series of interconnecting tunnels.
The mining operation for gems has been virtually the same since the days of Alexander the Great except for the modern addition of the water pumps for de-watering the pits. The supports for the excavations are still mostly the logs. Labour is provided as a share to the earnings as well as the equipment, materials and expenses such as food for workers.
The Clock tower in the city of Ratnapura is a fascinating place to visit in the early mornings. One can enjoy the scene of hundreds of people buying and selling gems. The genuine gem merchants allow the buyers to have the authenticity of the gems verified at the government run State Gem Corporation, Colombo or at a private yet government certified gem valuation agency prior to the transaction.