Deep within a silver and lean mine in Naica, Mexico, scientists discovered what is now known as Cueva de los Cristales, or Cave of Crystals, close to a decade ago. The gypsum crystals found in this cave measure as long as 11 meters (36 feet) and as thick as 1 meter (3 feet). While these crystals are beautiful and reminiscent of a Superman film, they have had scientists stumped since their discovery. The question was just how long these crystals had been growing in order to become this large.
Because growing a giant crystal in a laboratory creates difficulties because of the timescale required, they were unable to make an accurate guess as to the age of these crystals. However, thanks to a team of researchers from Spain and Japan and a new analytical technique, the age and the growth rate of these crystals has been determined and they have been a long time in the making. As much as 1 million years in the making.
The new technique utilizes a beam of white light aimed at the crystal to determine its properties. Scientists determined that the gypsum crystalized within the cave at temperatures between 54 and 58 degrees Celsius, or 129 to 136 degrees Fahrenheit. By submersing the crystal in mineral rich water, similar to what would have flowed in the cave before it was drained in 1975, the researchers discovered that the slowest growth would have occurred when the cave was 55 degrees Celsius. At this temperature, the crystals would have taken 990,000 years to form with a diameter of 1 meter. By increasing the temperature in the cave by one degree, or 56 degrees Celsius, the same size crystal could have formed in a little less than half the time, or around 500,000 years. This possible growth rate would work out to around a billionth of a meter of growth per day and is the slowest growth rate that has ever been measured.