Diamond formation
The formation of diamonds requires extremely harsh physical conditions, and can be used as jewelry, diamonds commonly known as diamonds are even more rare. Studies have shown that the formation temperature of diamonds is 900~1300 °C, and the pressure is 4~6Gpa, which is equivalent to the depth of 120~180km of the earth. After the diamond is formed deep underground, it reaches the surface through other geological activities such as volcanic eruptions. This process requires a very fast speed. Once the speed is insufficient, the diamond may be converted into other carbon allotropes (such as graphite) during the process of reaching the surface, and even oxidized to carbon dioxide at high temperatures.
Data obtained from some high-pressure tests indicate that pressure is more important than temperature during diamond formation. If the pressure is kept stable and the temperature is lowered, the diamond can still be in a stable state. But if the temperature stabilizes and lowers the pressure, the diamond will gradually lose its transparency and eventually transform into graphite.
Why do diamonds shine?
Here we must first explain what is transparent. In a narrow sense, it is the visible light that visible light can pass through the object. It is well known that light passes through an object and interacts with the object in a series of interactions, including reflection, absorption, and passage. If most of the light is absorbed, the object seen by the human eye is black; if a part of the light is absorbed and partially reflected, the object seen by the human eye is the color of the reflected light; if the vast majority of the light passes through the object, Only a small portion is reflected, and the object is transparent. The transparency of diamonds is very high, that is, the absorption rate of light is very low. Theoretically, diamonds containing no impurities and no defects in structure have no absorption in the range of 200~4800 nm. Diamonds used in jewelry are generally of higher purity and are naturally transparent to the naked eye. If the natural diamond is not strong enough at the time of formation, it will cause microscopic defects such as spots and lines inside the diamond, which will cause the defective position inside the diamond to interact with the light, which will make the diamond color. This is the yellow and brown industrial diamond. origin. Impurity atoms can microscopically change the structure of the diamond, which also causes the diamond to be colored. The blue diamond "The Heart of the Sea", famous for its movie Titanic, is blue because it contains impurities of boron atoms.
If it is only transparent, the diamond will not shine like this. It is well known that the rate of light propagation in different media is different, which is why light travels in the direction of interface propagation from one medium to another - that is, refraction. For different frequencies of light, the propagation rate in different media is different. This allows light of different frequencies to have different refractive indices. With this feature, complex light (such as white light) can be dispersed into monochromatic light through a certain dispersion system. The prism shown below is a good example of a dispersion system. After passing through the prism, the white light is broken down into seven color lights.
Jewelers have also taken advantage of the diamond's ability to disperse, giving diamonds a "fire flash." With a chromatic dispersion of 0.044, the diamond is among the best in many materials. The so-called fire color is the seven-color brilliance of diamonds. Because of the dispersion of the diamond, white light will be dispersed by the diamond after it is incident on the diamond, and it will be reflected after the seven-color light. The reflection mechanism can be represented by the following schematic diagram. This is why diamonds have fire.
In the eyes of materials scientists, diamonds are nothing more than pure crystals of carbon, and there is not much specialty. Perhaps because of the ad, the Chinese girl's fascination with diamonds, especially high-priced diamonds, is amazing. This, of course, includes the beautiful blessings that the girl hopes that her love and inner love can be as long as diamonds. The girls don’t have to worry about the price of diamonds. Diamonds are good, weddings are good, but it is a cut-off. If you want to live forever, it is king. If you can conquer the heart of a young man full of science and kindness, it seems to me that it is more commendable than receiving more expensive diamonds.