Optical properties of diamond

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Pure diamond color colorless transparent, but relatively rare. Most diamond crystals are different colors, the common is yellow, light yellow, green, light green, brown and light brown, followed by orange, black and so on. Red and blue diamonds are rare.

colour

gloss

According to the strength of the diamond luster, it can be divided into strong, medium and weak three kinds.

Transmittance, refractive index

Diamond has a high transmittance and high refractive index, which can be ground into fine particles to reflect more light and make it look brighter. High dispersion will also make the diamond produce "brilliance", the reason is that the white light is specifically dispersed by the diamond into monochromatic light. The dispersion value of diamond is the largest among natural gemstones. Theoretical analysis shows that pure diamond should be colorless. It can penetrate many wavelengths of light, including infrared and ultraviolet. This is due to the fact that the electrons in the diamond crystal are excited from the ground state to the first excited state, which is much higher than the energy of visible light (1.77-3.10 electron volts).

transparency

Transparency is one of the important indexes to measure the quality of diamond. Pure diamond transparent as water, with the diamond crystal containing trace elements and impurity elements are different, diamond transparency is divided into transparent, translucent, opaque three.

Electrical, magnetic and thermal properties

Electrical property

Generally speaking, diamond is a poor conductor of electricity. The electrical properties of diamond are mainly dopable, and diamond with semiconductor material properties can be obtained by proper doping. Compared with silicon and germanium, the electrochemical properties and Johnson valence primes of diamond are much higher.

magnetism

Diamond is a non-magnetic ore. However, some diamond crystals are magnetic because they contain magnetic inclusions such as magnetite and ilmenite.

Thermal conductivity

Under normal temperature conditions, the thermal conductivity of diamond is currently known to be better. The thermal conductivity of CVD diamond is between 1000 and 2000W/m·k, which is higher than that of natural diamond, 6 times higher than that of copper, and 13 to 26 times that of cemented carbide.

Heat resistance

The chemical properties of diamond are very stable and can withstand non-oxidizing acids at any high temperature, but cannot resist strong bases, oxates and molten metals. Oxidation occurs under pure oxygen conditions of 720 to 800°C, and under vacuum conditions of 800 to 1700°C, a thin graphitized layer is formed, and under the protection of nitrogen and hydrogen, even if oxidation does not occur at 1000 °C.

Optical properties of diamond

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Chemical properties of diamond

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Chemical properties of diamond