To prevent getting lost, the elevator goes directly to the safety islandNewspaper man Liu YaEast A
Take science home
Author:ziv
Not long ago, the Frenchman Navas went to a space force base in Florida to see the launch of the "Peregrine Falcon" lunar lander. After visiting, he heard that there was a nice park in ArkansasIf you're lucky, you might find a diamond
The standard "Diamond Hunter" set comes with a military shovel, a set of screens, and a bucket of water, as well as a sieve (**flickr-ejourna) that sieves mud in the water
When he arrived at the park, he rented a set of "diamond hunter" gear and started digging for diamonds。"It's a lot of work. Navas said. His main method is to find everything that stands out on the ground.
After most of the day of excavation,He took a few small items that appeared to be diamonds to the park's Diamond Discovery Center。The staff told him,He found a 746 carat brown diamond
Diamonds found in Navas (**Arkansas State Parks).Where do diamonds come from?
The only component of a diamond is carbon, and each carbon atom is combined with four other carbon atoms to form a diamond. It sounds very simple, but between these carbon atomsThe chemical bonds are very tight, forming a three-dimensional network structure, which makes the diamond incredibly hard, crystal clear when free of impurities, and light can pass through at any angle. 
The tetrahedral structure of a diamond (**wiki) is in graphite, which is also composed of carbon, with each carbon atom bound to only 3 other carbon atoms, which are stacked on top of each otherThe connection between layers is weakThe structure is looser, and the light is trapped between these atoms, so they look pitch black. 
The structure of graphite and its layered crystal structure (**wiki) is so dense because they are usually formed very deep below the surface, about 150 250 km. The pressure there is approximately50,000 times the pressure on the Earth's surface, andThe temperature is very highand can be up to 1600. In such a high-temperature and high-pressure environment, it takes about 1.03 billion years for a diamond to be born naturally. However, not all diamonds are considered jewelry, most diamonds can only be used for industrial purposes, and a few are of good quality to be classified as gem-quality diamonds. Jewelers assign 4Cs to these gem-quality diamonds, which are:Cutting processcolorClaritywithCarat, carat is the unit of weight of a diamond, 1 carat is equivalent to 200 milligrams. An average of 250 tonnes of diamond ore is mined to obtain a 1 carat gem-quality diamond. How do diamonds get to the surface?
It's gold that always shines, and so do diamonds. Diamonds can only be formed deep underground, where there is no sunlight, and we are not able to go directly to the center of the earth to find diamonds, but some diamonds will rise near the surface. Because the temperature in the ground is too high, hereThe gas will continue to expand and rise, rising with the deep mantle. When gas rushes out of the ground with lava flows, erupting volcanoes are formed, and diamonds are carried out by the surrounding magma. 
Schematic diagram of volcanic pipes (**wiki) Magma cools to form igneous rocks, some of which areKimberlite, the parent rock of diamonds。Not all igneous rocks contain diamonds, and if the igneous rocks are shallow enough to form a high-temperature and high-pressure environment, there are no conditions for the formation of diamonds. WhileKimberlite is formed by the cooling of magma from the deep mantle, so they are very rare. In addition to diamonds, kimberlites contain a number of minerals whose composition and crystal morphology suggest that they are formed in the high temperature and pressure environment of the deep mantle, just like diamonds. 
Diamonds in Kimberlite (**ASU) This Diamond Cratter Park in Arkansas is just above a volcanic pipe that has been eroded over the yearsIts bedrock, also known as kimberlite, has been exposed to the surface and is ideal for digging for diamondsMoney password
If you want to expand the scope of your diamond search, you can look at:"Craton".(craton), these places often contain rock formations where diamonds are hidden. 
Global craton distribution (**Liu Mingqi, 2018)Cratons are also known as "stable massifs", and they were formed in ancient timesSome cratons are even more than 2 billion years old。They are the most stable part of the continental lithosphere, running through the Earth's top two layers – the crust and the upper mantle. The craton survived the cycle of continental mergers and **, and contains many bedrocks containing ancient mineral crystals. How is a diamond's color formed?
The color of a natural colored diamond usually comes from the chemical elements it contains, such as:Boron contains it to appear blue, sulfur to appear green, and nitrogen to yellowWait a minute. However, trace elements have not yet been found in pink diamonds, and it is thought that its color is caused by the distortion of the diamond's crystal lattice. There are many types of brown** in diamonds, which can be due to exposure to nitrogen, nickel impurities mixed into it, or due to intense pressure, the internal structure of the diamond is deformed, affecting its ability to reflect light, giving it a brown appearance. 
Brown diamonds from the collection of the Museum of Natural History, Washington, D.C., USA (**wiki).Brown diamonds are the most common natural colored diamonds。For many years, they were often used for industrial purposes, and in the past there was not even a grading of brown diamonds. However, in the 80s, jewelers discovered the unique charm of brown tones, which are now a popular color. Great place to pick up diamonds
Cox, an administrator at Diamond Crater Park in Arkansas, said many of the large diamonds here were found on the surface. The Park Service regularly loosens the soil in the Diamond Search Area, which promotes natural erosion of the natural surface soil.
People hunting for treasure in Diamond Crater Park (**wiki).
Two days before Navas came to dig for diamonds, it had just rained here, and the rain washed away part of the floating soil, exposing surface rocks, tooMake diamonds easier to spot。In Arkansas Ore Pit Park, the most common diamonds are clear, brown, and yellow. And here's moreNatural amethyst, garnet, jasper, agate and many more。Since the park was founded in 1972, visitors have found more than 35,000 diamonds here. The biggest is:40.23 carat Uncle Sam diamonds, which is also the largest diamond ever unearthed in the United States.
The cut Uncle Sam's diamond (left) is now visited by many visitors at the location where the diamond was found (**wiki tripadvisor).
This time, the diamond found by Navas is ranked 8th here, which is also a big catch!
References: 1].