What is the refractive index of diamond?

The refractive index of diamond is 2.4 17.

The refractive index of diamonds is basically the same, mainly because diamonds are equiaxed crystals and their optical properties are isotropic. The refractive index is basically fixed at 2.4 17, so the refractive index is also a powerful parameter to judge the authenticity of diamonds.

Refractive index of other gemstones

Every gem and diamond has its corresponding refractive index, such as 1.66 for jadeite, 1.762~ 1.770 for ruby and sapphire,1.577 ~/kloc-0 for aquamarine and/.583 for tourmaline. By accurately measuring the refractive index of a gem, we can roughly judge what kind of gem the gem to be tested may be, and then combine with other identification methods to determine the species of the gem.

Extended data:

Identify cases

1, crystallization habit

Synthetic diamonds are usually cubic, octahedral and their aggregates.

Natural diamonds are usually octahedral, rhombic dodecahedron and their aggregates, and there are also common triangular lamellae twins.

Step 2 color

Synthetic diamonds are often yellowish brown and often turn blue, orange, pink, brown and golden yellow after irradiation.

98% natural diamonds are colorless-light yellow series.

3. Internal texture

Synthetic diamond: it can show dendritic or cross texture.

Natural diamond: triangular dents or triangular seats are common on the surface, and texture related to structure is often displayed inside.

Step 4 zoom in and observe

Synthetic diamond: seed crystal and its phantom zone, various forms of metal inclusions.

Natural diamonds: no metal impurities.

5. Visible light absorption spectrum

Synthetic diamond: there is no absorption line of 4 15.5nm, and the absorption peak of 658nm and the total absorption below 500nm can be measured at the low temperature obtained by liquid nitrogen.

Natural diamonds: most of them are absorption lines of 4 15.5nm.

6. Ultraviolet fluorescence

Synthetic diamonds: usually no fluorescence in long wavelength, yellow-green and orange-yellow fluorescence in short wavelength, "Maltese cross zoning" phenomenon, obvious phosphorescence.

Natural diamond: blue-white fluorescence in long wave, weak or inert in short wave.

7. Cathodoluminescence instrument

Synthetic diamond: similar to ultraviolet fluorescence distribution, different growth areas show different fluorescence bands.

Natural diamonds: mostly irregular.

Because when natural diamonds grow, the environment will always change, but the growth environment of artificial diamonds is unchanged.

8, infrared spectrum

Synthetic diamond: 1 130 absorption passband of light beam

Natural diamonds: absorption bands of light beams 1 176 and 1282.

9. Conductivity

Synthetic diamonds: Some may have electrical or thermal conductivity.

Natural diamonds: Except for blue diamonds, they are semi-conductor, non-conductive and non-magnetic.

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