Azufral is a volcano located in the department of Nariño in southern Colombia, 12 km (7 mi) west of the town of Túquerres. Its name derives from the Spanish word for sulfur, azufre. The volcano is considered semi-dormant but there are numerous fumaroles 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 (English: Green Lake) at 3,970 m (13,025 ft). The lake is 1,100 m (3,600 ft) long and 600 metres wide and its bright green color is a result of the sulfur and iron-based deposits in the crater.