The largest cave, the candle cave, has several speleothems (formations resembling frost in extremely cold climates) formed over the past 20 years. Although it is the only cave in the world with these formations, it runs the risk of disappearing as a result of the cooling down of its walls. the cave is distinguished by the opalescent, pearly color of its crystals.

Small, thin, delicated speleothems (the candles)
that developed around the surface of the crystals
in the upper chamber of the Candle Cave.

Candles’ cave is the latest mine cave found at Naica. What makes the cave special is the presence of many small, thin and very delicate speleothems (the candles), which developed on top of the gypsum crystals in the upper room of the cave. The “candles” grew over a short span, only some 20 years or so, commencing just after the artificial lowering of the groundwater level. It is the only known cave not only within the Naica mine but in the entire world, in which these peculiar speloethems had the unique possibility to develop. It has a temperature of 43-45ºC, while its relative humidity is less than 80%.

The cave has a total length of about 80 meters and it consists of two main large rooms in two levels, partially superimposed. The average height of the chambers is 3-4 meters and in some areas over 10 m wide. A 3 meter climb is required to reach the upper room.

See: Tullio BERNABEI, Paolo FORTI, Roberto VILLASUSO:
A New Gypsum Speleothem from NAICA (Chihuahua, Mexico):
The Sails. International Journal of Speleology. January 2007.