Red diamond
Natural red diamonds are very rare. At present, it is generally believed that the color of natural red diamonds is formed by plastic deformation and nitrogen doping.
If it is only due to plastic deformation, it is possible to produce purple-red pink with high saturation. If the plastic deformation diamond contains a certain amount of nitrogen, it can absorb the short-wave blue-violet light in the sun, and plastic deformation absorbs some orange, yellow and green light, making the diamond red.
In fact, more magenta diamonds are mainly produced by plastic deformation and color center coloring.
Orange diamond
Natural orange diamonds are very rare, and there are almost no pure orange diamonds. At present, the color of orange diamonds is mostly brown and orange. Because there are few natural orange diamonds, there is little research on the causes of their color. It is generally believed that the color of orange diamonds is produced by a wide absorption band centered at 477 nm. In addition, diamonds with high nitrogen content have strong color centers and can also produce orange.
Yellow diamond
Yellow diamonds are the most common in colored diamond. Yellow diamond can be regarded as an extension of colorless-light yellow series, that is, when the saturation of a yellow diamond is greater than Z+ colorimetric stone, it no longer belongs to the "colorless" diamond of D~Z color class, but belongs to the colored diamond series together with diamonds of other colors.
The color of yellow diamond is produced by impurity nitrogen in the crystal lattice of diamond. Most natural yellow diamond crystals have N3 color centers and belong to type Ia diamonds. Only a small amount of natural yellow diamonds belong to Ib type. In general, the saturation of Ia yellow diamonds with the same nitrogen content is less than that of Ib yellow diamonds.
Green diamond
Natural green diamonds are very rare. Green diamonds are usually formed by long-term natural irradiation. When the radiant energy is higher than the crystal threshold, carbon atoms are knocked out of the lattice position, forming vacancies, changing the crystal structure of the diamond, thus producing a series of new absorption, which can make the diamond green.
blue diamond
Blue diamonds contain no nitrogen, but very little boron. Boron atoms produce an acceptor band in diamond crystals. The acceptor band can absorb near-infrared radiation and long-wave visible light, thus making the diamond appear blue. The energy difference between the acceptor band and the valence band is very small, and the valence band electrons can jump to the acceptor band under the action of heat, making the diamond conductive, so the blue diamond is a semiconductor.
Pink diamond
The color of natural pink diamond is mainly produced by the plastic deformation of diamond crystal. In the high temperature and high pressure environment of the mantle, the crystal structure of diamond is deformed by the uneven lateral force. This plastic deformation changes the physical and optical properties of diamond crystal at the defect.
carbonado
In the past, black diamonds were mainly used for industrial purposes and rarely used for jewelry. In recent years, large black diamonds have been gradually accepted by people, and black diamond jewelry has a popular trend. The color of most natural black diamonds is caused by graphite contained in the crystal.
Under the microscope, these graphites are generally tiny flakes, which are evenly distributed in diamond crystals. Because graphite has a very high absorption rate of visible light, it absorbs almost all the incident light. Because of the high refractive index of diamonds and the high reflectivity of surface light, all cut black diamonds, like diamonds of other colors, have sacred shining points on their surfaces, which is very attractive. 20 12, 1 June, scientists confirmed that black diamonds were formed after the survivors of supernova explosion fell to the earth.
(MPCVD-4 equipment, a new carbon equation material)