How long does it take for gemstones and crystals to form? It was believed to be years or thousands of years. It seems that it is not so true. According to a study by Rice University, some minerals lack this patience. It’s titled Episodes of rapid crystal growth in pegmatites. It was published this week in the journal Nature Communications and deals with crystals that form in hours.
How they are formed
What are pegmatites? They are venous formations that usually contain large crystals and elements that are difficult to find in the earth’s crust. Aquamarine, emerald, garnet, zircon or topaz are just a few of them. Tantalum and niobium usually occur there. Another common finding is lithium, an important part of electric car batteries.
When do pegmatites arise? When it rises, magma cools down in the earth. They show some of the largest crystals on earth. Take the Etta Mine in South Dakota, for example. You can see crystals made of spodumene, a lithium-rich mineral. They can measure up to 12 meters and weigh around 37 tons. How can such large crystals form on pegmatites?
“The crystal size is traditionally related to the cooling time,” says Cin-Ty Lee. It belongs to Rice University. “The idea is that large crystals take time to grow.” “But pegmatites cool down relatively quickly. Sometimes they present the largest crystals on earth in a few years. How can this be possible? “.
They collected crystal samples from a pegmatite mine and made hundreds of measurements. “We examined crystals that are 1 centimeter wide and more than two centimeters long,” says Patrick Phelps, also author of the study. “We found that they grew in a matter of hours. And nothing suggests that the physics would be any different for larger crystals a meter or more in length. Such larger crystals could grow in a few days. ” Add.
They calculated how fast the crystals in the samples grew. According to Phelps, the rapid growth rates came as a big surprise. “Pegmatites are pretty short-lived, so we knew they had to grow relatively quickly,” he said. But that was surprising. I went to Cin-Ty’s office and asked her, “Can you do that? I don’t think that’s right. He was still thinking of a time scale of thousands of years. And those numbers meant days or hours. Cin-Ty replied, “Well, why not? Why can’t it be right?” Says Phelps. The crystals that form in hours surprised the researchers.
«We had worked with math and physics. That part was good, ”adds the author. “We didn’t expect these minerals to form so quickly. But we couldn’t find a reason why this wasn’t plausible, “sentence.