Why can diamonds shine brightly, but glass can't?


What is the most difficult and do you like it the most?

Of course, diamonds!

Diamonds are loved not only for their rarity, but also for the fact that they have many properties that are not found in other things. For example, it is the hardest element known in nature, the highest refractive index transparent substance, one of the most chemically resistant substances, and the most expensive luxury.

Legacy forever

Diamonds have always radiated an incredible light that has fascinated many people. Why can diamonds shine and clear glass?

Diamonds don't shine on their own

In a dark room, the diamond is not visible, which means that the light does not come from inside the diamond. The reason why a diamond can shine is mainly due to its unique light refraction, reflection and scattering properties.

Natural diamonds are mainly mined in diamond mines in Africa, Russia and other places. They are mined at a depth of hundreds of kilometers underground and brought to the surface as a result of the movement of the earth's crust or volcanic eruptions. The diamonds found are as simple as glass shards, nothing special.

Rough Diamond

But after the workers in the diamond processing workshop carefully cut, processed and polished it, some of the precious qualities contained in the diamond came out to the fullest and became a precious thing that everyone loves.


What magic did the craftsmen use on the diamond to make it reborn? It comes down to two words: angle.


When a gem designer receives a rough diamond, the first thing they do is carefully examine it to see what impurities and cracks are inside the diamond. These impurities and cracks form during diamond formation and interfere with the direction of light within the diamond, so they must be carefully avoided. Sometimes, due to some imperfections, the designer has to make the decision to split a large diamond into several small diamonds in order to achieve the best effect and the highest value.

Diamond cut

After cutting a rough diamond, the designer needs to design according to the shape to cut and polish the largest diamond and make the most of the remaining material.


You may have noticed that a typical rhombus is a cone-shaped polyhedron with a large top and a small bottom, and the top is a polyhedral table. All designs are designed to achieve the same goal, which is to allow light entering the diamond to refract as much as possible between the different facets of the diamond, and finally reflect off the top surface.

All the angles of the diamond's facets are precisely calculated and carefully polished to ensure that the light travels in the correct path. As long as there is a slight difference, a satisfactory effect cannot be achieved.

Refraction of light

Diamonds are faceted and polished using diamond-coated grinding wheels. The workers are well trained, work neatly and are always up to date with the grinding.

Diamond processing

Is glass suitable?

Returning to the original question: can you use the same clear glass to simulate a diamond to achieve the same effect as a diamond?

Answer: no.

Although glass is as transparent and hard as diamond, it is an amorphous (some call it glassy) substance, while diamond is a crystal composed of carbon atoms. The difference between them is manifested not only in hardness, but also in a huge difference in the refractive index of light.

Generally speaking, the refractive index of diamonds for light is as high as 2.42, while the refractive index of ordinary glass is only about 1.5. The crystal is a silicon dioxide crystal, and its refractive index is only about 1.55, which is slightly higher than that of glass.

Refraction of light

From this we can see that diamonds imitating glass or crystal cannot achieve the same refractive effect. Of course, if the sharpening angle is carefully thought out, it is not difficult for a non-professional to deceive.


Speaking of this, you might think that all the credit goes to the light, but that's not correct. For a diamond to shine, it must have not only light, but also darkness.

If you're savvy, you should have discovered this rule: almost all diamond images with shock effects should have a black or dark background. Just as safflower needs green leaves, the dark background around a diamond will also reflect off some of its facets. These dark areas reflect the refraction of light, highlighting the color and charm of the light.

Now to summarize:

The brilliance of diamonds depends not only on the ability of their own excellent refractive index to manipulate light, but also on the superior skills of designers and craftsmen in designing and cutting diamonds.

Through careful analysis, careful design and precise processing of rough diamonds, each facet of a diamond can accurately reflect the incident light, so that we can observe multi-colored light from the right angle.

Due to the inherent difference in refractive index of glass, it is difficult to achieve the same effect as diamond. But it is still possible to deceive the layman.