Sri Lanka formerly Ceylon, Island country in the Indian Ocean, off the southeastern coast of India. Highlands make up Sri Lanka’s south-central region and core, with narrow gorges and deep river valleys. The surrounding lowlands include hills and fertile plains. The developing mixed economy is largely based on agriculture, services, and light industries. Clothing, tea, gemstones, and rubber are exported. The island is world-famous for its gemstones, which include sapphires, rubies, and topaz.