Hierve el Agua mountainside. The water has a temperature of . As the water runs down the rock face, it forms large stalactites similar to those found in caves. The flow of water from the spring varies significantly between the dry and rainy seasons. 95% of the surface rock formations are of calcium carbonate; however, lower layers of both rock and water currents are little known as they are sealed by the above layers. The calcium carbonate gives the formations a white or near white appearance, but other minerals that can be present in the water, such as silver, barium and iron can
Cave of the Crystals deposits of silver, zinc and lead. The Cave of Crystals is a horseshoe-shaped cavity in limestone. Its floor is covered with perfectly faceted crystalline blocks. Huge crystal beams jut out from both the blocks and the floor. The crystals deteriorate in air, so the Naica Project attempted to visually document the crystals before they deteriorate further. Two other smaller caverns were also discovered in 2000, Queen’s Eye Cave and Candles Cave, and a further chamber was found in a drilling project in 2009. The new cave, named Ice Palace, is deep and is not flooded, but its crystal formations are