The hot mineral spring Garm-Chashma (the name translates from Tajik as ‘hot spring’) is situated at an elevation of 2,325 m above sea level, on the western slope of the Shakhdara Range, in the middle course of the Garm-Chashma River, 42 km southwest of the city of Khorog, Ishkashim District of Gorno-Badakhshan Autonomous Province, Tajikistan.
The spring is at least few thousand years old, because this is the minimal period required for the formation of such enormous travertine deposits (sinter) as cascade down to the river in Garm-Chashma. These cascades, bright white, yellowish and reddish brown, have the form of a curving bank 1.5 km long, 35-45 m wide and from 7 to 35 m high. The mineral water that comes from deep under the ground forms a series of small and large fountains, from 10 cm to 1.5 m in height, lining strictly along the crest of the ridge. The average flow of all the outlets is between 5 and 7 litres of hot water per second. The water brings to the surface calcareous-calcite balls of regular shapes, from 0.5 cm to 3-4 cm in diameter, which come as part of a white mixture of water with limestone, gypsum and chalk.
In the travertine bank there are a number of natural pools of various sizes, from 0.5 to 20 sq m in area and up to 0.5 m in depth. They are filled with turquoise hot water containing iron, aluminium, magnesium, strontium, fluorine and other chemical elements. There also are large quantities of hydrogen sulphide (170 mg/l), silicic acid (135 mg/l) and carbonic acid (381 mg/l). The temperature of the water is around 62°C at the outlets. The temperature of the pools ranges between 38°C and 50°C, depending on the distance from the spring. The outer walls of the reservoirs are made particularly charming by numerous stalagmites attached to them, each of the structures painted in different shades by multi-coloured algae covering them. The bottom of the largest pool is spread with a thin layer of calcium carbonate and sulphur deposits.
The area also features carbonaceous mineral springs with a permanent temperature of +14 degrees Celsius, the water from which locals use for cooking and drinking.
In 1957 the Garm-Chashma sanatorium was built in the place.