How do diamonds form? How many years does it take for diamonds to form
Diamond is the hardest material on the earth, and it's also a very expensive luxury! As the saying goes, the rarity of a diamond and its unique hardness make it valuable. Do you know how diamonds are formed? Let's have a look with Xiaobian!
Diamonds are glittering but expensive. As the diamond monopoly De Beers exaggerates the value of diamonds, diamonds are loved by people all over the world. Diamond is the symbol of Japanese Marriage and the first choice of American engagement ring. So, how are diamonds formed? How are diamonds found?
Structural characteristics of diamond: diamond is composed of carbon element, which is a crystal of carbon element. Its hardness is 10. It is the natural mineral with the highest hardness in nature. Its density is 3.53 (& plusmn; 0.01) g / cm3, refractive index is 2.417, and dispersion is 0.044. It is the product of diamond after cutting and grinding. About one fifth of the diamond minerals can reach the gem level. It is called gem level diamond, and it is called 'diamond raw stone' or 'diamond blank' abroad. After cutting and grinding the drill blank into a certain cutting type, it is called naked drill, and abroad it is called finished diamond or polished diamond. The English name diamond, from the Greek adamant, means' hard, inviolable, invincible '.
Diamond and graphite are composed of carbon. Diamond and graphite are formed under different temperature and pressure conditions, and they can transform each other under the change of temperature and pressure conditions. Diamond belongs to cubic crystal, hardness is 10, graphite belongs to hexagonal crystal, hardness is 1, and their crystal structures are different, so they are two homomorphic multi image variants of crystalline carbon. Only under certain pressure and temperature can carbon crystallize into diamonds.
Diamond formation: the earliest natural diamond was formed in the interior of the earth, with a temperature of 900-1600 ℃, a pressure of 4.5-6 & times; 109pa, and a depth of 130-200km underground, which is the environmental condition for diamond formation. In theory, as long as the conditions are met, diamonds can be formed in any period. At present, most of the diamonds mined are formed in 3.3 billion years and 1.2-1.7 billion years ago, and Most of them are excavated and mined in the ancient stable continental area of the earth. The carbon for diamond formation comes from magma melting in the mantle or from crustal movement. The carbon in the crust is brought to the depth of the earth and crystallized into diamond under suitable conditions.
There is also a way to produce diamonds from the outside. When meteorites hit the mainland, the high temperature and pressure generated in an instant may also produce diamonds. However, the diamonds produced in this way are usually relatively small and of poor quality. Generally, they do not have economic value and cannot be used as diamonds for jewelry processing.
Discovery of diamonds: the first discovery of diamonds was in India. With people's desire for diamonds, the diamond exploration and mining industry has become more and more popular. Diamond deposits are divided into primary and secondary deposits. The primary ore is generated by the geological movement of the earth. The seismic and volcanic activities bring the diamond rich minerals to the surface or near the surface of the stay rich areas, most of which are kimberlite and K-Mg lamprophyre rich in diamonds, as well as the fillings near the crater and the rock wall and the root deposit in the rock bed. The secondary ore is transported and deposited from the primary ore under the action of nature. Most of them are weathered and washed by rain, and remain in the hillside, river and coast to form ore deposits, most of them are placers.
The process of diamond formation and discovery is similar to that of precious metals such as gold. Since the 21st century, diamond prices have maintained a steady growth trend of only rising but not falling, which has gradually become the first choice of investors.