Ratnapura-located at 103 km from Colombo-is the famous gem-mining town of Sri Lanka. In fact the name Ratnapura literally means, the City of Gems. Sri Lanka has the greatest concentration of gems on earth and is ranked among the top five gem-bearing nations. One can find all types of gems in Ratnapura-from familiar to exotic. These include: white, yellow, pink, orange, purple and blue star sapphires, ruby and star ruby, cat's eye, topaz, amethyst, moonstone, aquamarine, tourmaline, garnet, zircon, spinel, alexandrite, citrine, etc., and the exotic ones such as patite, sinhalite, ekanite, enstatite, andalusite, kornerupine, etc., sought by the connoisseur.

City Travel Guide
Apart from the gems other places of tourist interest are:

Maha Saman Devale: A devale is a shrine dedicated to either a god of the Hindu pantheon or a local deity, which is usually situated within a Buddhist vihara or temple. This unique devale, only a short distance from Ratnapura, is dedicated to Saman-the tutelary deity of Adam's Peak.

Annual Fair/Perahara: There is an annual fair and perahera in the month of July-August, which is among the largest to be held in the country. Its main feature is the Maha Baha a giant effigy who like the Roman Janus has two faces-one pink-cheeked and smiling, the other dour and black-visaged.

Sinharaja: The highland forest of Singaraja, located near Ratnapura is a nature lover's delight. It is the last remaining original tract of rainforest on the island.

Ratnapura is also one of the base camps to the pilgrimage trek to Adam's Peak.

Source: Tourism-Sri Lanka