Azufral is a volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 located in the department

Departments of Colombia

Colombia is an unitary republic formed by thirty-two departments and a Capital District . Each department has a Governor and a Department Assembly , elected by popular vote for a four-year period. The governor cannot be re-elected in consecutive periods...

 of Nariño

Nariño Department

Nariño is a department of Colombia named after Antonio Nariño. It is in the west of the country, bordering Ecuador and the Pacific Ocean.Its capital is Pasto, other important cities include Tumaco, Ipiales.-Municipalities:# Albán# Aldana# Ancuya...

 in southern Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, 12 km (7 mi) west of the town of Túquerres

Tuquerres

Túquerres is a town and municipality in the Nariño Department, Colombia....

. Its name derives from the Spanish

Spanish language

Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

 word for sulfur

Sulfur

Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

, azufre. The volcano is considered semi-dormant but there are numerous fumarole

Fumarole

A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...

s in the summit crater. The summit of the volcano has an altitude of 4,070 metres and the north-western side of the crater contains a crescent-shaped lake named Laguna Verde (Green Lake) at 3970 m (13,025 ft). The lake is 1100 m (3,608.9 ft) long and 600 metres wide and its bright green color is a result of the sulfur and iron-based deposits in the crater. There are also two other much smaller lakes in the crater, Laguna Negra (Black Lake) and Laguna Cristal (Crystal Lake).

The volcano lies within a nature reserve, the Reserva Natural del Azufral, created in 1990. The reserve covers an area of 5800 hectares (58 km²) and is free of charge to enter. As Azufral is semi-dormant there are no restrictions on ascending the volcano and visiting the Laguna Verde: there is a road that climbs to within 1.5 kilometre (0.93205910497471 mi) from the summit, and the remaining distance can be covered on foot via a trail.