After World War II, the United States and Europe, the market is retracted all the gold the US Treasury. No similar little gold wedding necklace, gold rings valuables, always expensive and was not very grand. Ever since, the world diamond monopoly De Beers sweater jeweler saw an opportunity for a "a diamond is forever" as the slogan, the success of the diamond to sell to the public. "A diamond forever" in Chinese is translated into "A diamond is forever, diamond is forever." Phrase ad like a curse captured thousands of girls, and now diamonds have become an integral part of marriage.
Diamond formation
Diamond formation requires extremely harsh physical conditions, and can be used as jewelry, commonly known as diamond diamond is more rare. Studies have shown that diamond formation temperature at 900 ~ 1300 C, a pressure of 4 ~ 6Gpa, roughly equivalent to a depth of 120 ~ 180km Earth. Diamond is formed deep underground after arriving at the surface by volcanic eruptions other geological activity. This process requires a rapid rate, once the speed is not enough to reach the surface of the diamond in the process may be converted into other carbon allotropes (eg graphite), even at high temperatures is oxidized to carbon dioxide.
Through a number of high-voltage test data obtained shows that in the process of diamond formation, the pressure is more important than the temperature. If the holding pressure is stabilized, lower the temperature, the diamond is still in a stable state. However, if the temperature is stable reduced pressure, the diamond will gradually lose transparency, it will eventually be converted into graphite.
Why diamonds sparkle?
Here to first explain what is transparent. Narrowly defined, is in the human eye, visible light can pass through objects. As we all know, just at the right time through the object and the object will be a series of interactions, these interactions include reflection, absorption and through. If most of the light is absorbed by the human eye to see objects is if a portion of the frequency of the light is absorbed portion is reflected by the human eye to see objects that are reflected by the color of if the majority of the light passes through the object, only a small portion is reflected, the object is transparent. High transparency of the diamond, the light absorption rate is very low, in theory, free of impurities, free of any defect in the structure of the diamond without any absorption wavelength within the range of 200 ~ 4800nm. Used in diamond jewelry is generally higher purity, the naked eye is naturally transparent. If natural diamonds are formed when the pressure is not enough, the diamond will internally generate points, lines and other microscopic defects, resulting in the role of the diamond inside position of the defect and the occurrence of light, make colored diamonds, which is yellow and brown diamond industry origin. Impurity atom can make the diamond structure on a microscopic produce small changes, which will lead to diamond with a color. Because the movie Titanic famous blue diamond "Heart of Ocean" is because it contains a boron atom impurities in blue.
If only transparent, so the diamond will not shine. Is well known, the propagation speed of light in different media is different, it is a change in the light propagation direction of another interface from one medium to the medium - the reason - that is refracted. For light of different frequencies, the propagation velocity in different media is not the same. This allows many different frequencies of light have different refractive indices. With this feature, through a certain dispersion system, polychromatic light (including white) can be dispersed monochromatic light. Prism shown below is a good example of the dispersion system. After the white light through a prism, it is broken down into seven colors IPL.
Smart people use refraction diamond jeweler, and a series of diamond grinding process, so that the diamond are brilliant, the girls became a diamond ring on. Firstly, the diamond is the higher refractive index, 2.417 (589.3nm sodium light irradiation was detected) diamond refractive index. Light from the optically denser medium to the optically thinner media will totally reflected by the following chart we can see the wisdom of the jeweler. Through clever cutting, allowing the light incident on the diamond is totally reflected back. It is also a very high diamond processing requirements reason, once the process is not good, the impact on the diamond luster will be very large.
Jewelers also use the diamond dispersion and strong features, so that the diamond had a "fire color" (fire flash). Dispersion of a diamond 0.044, among the best in many materials. The so-called fire-color, seven-color diamond is the glory. Because the role of diamonds dispersion of white light incident on the diamond after diamond will be dispersed, after becoming IPL Rainbow reflection, the reflection mechanism can be represented by the following schematic. That is why the diamond with the color of fire.
A diamond really is forever right?
Faye Wong Wang days later saying the lyrics sing well: nothing will last forever. Diamond certainly not. Even aside all high-energy radiation and high temperature oxidation and other man-made diamond destruction factor, at normal temperature and pressure, the diamond will be transformed into another elemental carbon. Junior high school chemistry textbooks used in terms of time allotrope mentioned, a milk fellow brothers diamond graphite, at normal temperature and pressure than the diamond-stable, if the time is long enough, all the girls rings inlaid diamonds, It will become graphite.
Why is this? Analyzing the stability of the structure of a substance, it can be free to look at this structure is not the lowest. What is it free energy? My understanding is that at a certain temperature and pressure, the energy structure of the material which can be disposed of, and this energy is higher, the more the material wants energy consumed, energy consumed in the future structure of the material may also change. At a certain temperature and pressure, the material tends to be at its lowest free energy structure.
If the structure and elemental carbon free energy to establish a relationship, and the result is shown below. The horizontal axis shows the arrangement of carbon atoms, the vertical axis represents the free energy of the system. A representative of graphite, B on behalf of the diamond, the result is obtained based on the ambient temperature and pressure conditions. From the figure we can see the structure of graphite and diamond are images of minimal value, and a lower free energy of graphite, so that the graphite is more stable than diamond. But at a minimum due to the diamond position, then changed his words energy structures will rise, so the diamond is also a stable structure form at normal temperature and pressure, called metastable structures.
While under normal temperature and pressure in diamond becomes graphite, but the young bride does not have to worry about your ring. Although this conversion can be carried out spontaneously from the thermodynamic sense, but the rate is extremely slow. From the graph we can see that elemental carbon structure by the B switch to A, you need to cross a very high energy peaks, which also makes the conversion of diamond to graphite becomes difficult. Not a few hundred thousands of years, sparkling stone on your ring does not become dark graphite. Life is only a hundred years, from this perspective, can be considered a diamond is forever it.
Materials scientists in the eyes, but the diamond is a relatively pure crystals of carbon, and not much special. Perhaps because the phrase ad, Chinese girl for diamonds, especially diamond expensive fascination people extremely amazing. This of course includes the girls want to and within months his love can last forever like a diamond, a blessing. The girls need not so entangled in the diamond price. Diamond Ye Hao, Ye Hao wedding, but is a mere formality, to forever, to rein in his heart, is king. If you can rein in a scientific and kindness filled the boy's heart, in my opinion, we received more than expensive diamonds are commendable.
) (Author: Dragon eight children)
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