User:MidoriWolf07/sandbox

The main chamber contains giant selenite crystals (gypsum, CaSO₄·2 H₂O), some of the largest natural crystals ever found. The cave's largest crystal found to date is 12 m (39 ft) in length, 4 m (13 ft) in diameter and 55 tons in weight. The magma within makes the cave unbearably hot and humid, with air temperatures reaching up to 58 °C (136 °F) with 90 to 99 percent humidity. The cave is relatively unexplored due to these factors. Without proper protection, people can only endure approximately ten minutes of exposure at a time. Nevertheless, the cave is the world's most remarkable display of natural mineral formations. the

Formation of the crystals

Naica lies on an ancient fault above an underground magma chamber, which is approximately 2-3 miles (3-5km) below the cave. The magma heated the ground water which was saturated with sulfide ions (S²⁻). Cool oxygenated surface water contacted the mineral saturated heated water, but the two did not mix due to the difference in their densities. The oxygen slowly diffused into the heated water and oxidized the sulfides (S²⁻) into sulfates (SO₄²⁻). The hydrated sulfate gypsum crystallized at an extremely slow rate over the course of at least 500,000 years, forming the enormous crystals found today. The key to this process is the slow diffusion of oxygen from the cool, low density surface water into the hot, high density ground water. The crystals have grown steadily and slowly, but they will grow no further unless the cave floods once again.