Igneous rock the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate. Hence such rocks are smooth, crystalline and fine-grained. Basalt is a common extrusive igneous rock and forms lava flows, lava sheets and lava plateaus. Some kinds of basalt solidify to form long polygonal columns. The Giant's Causeway in Antrim, Northern Ireland is an example. The molten rock, with
Cave of the Crystals only endure approximately ten minutes of exposure at a time. The cave was discovered by the brothers Eloy and Javier Delgado. It has since been allowed to re-flood, with the cavern now filled once more with the water rich in minerals required for the crystals to grow. A group of scientists known as the "Naica Project" have been heavily involved in researching these caverns. Naica lies on an ancient fault above an underground magma chamber which is approximately below the cave. The magma heated the ground water which was saturated with sulfide ions (S). Cool oxygenated surface water contacted the