Why Diamonds are white and Graphite is black but both are Carbon

Why can Diamonds be white and Graphite is black even though both are made from Carbon?

Diamond is the hardest known mineral and extremely hard to scratch - on the other hand Graphite, which is used in pencils is soft and crumbly.

It is hard to believe that Diamonds and Graphite are actually the same element - Carbon.

Carbon - Building Block of Our Planet

Carbon is the fourth most abundant element on our planet - only hydrogen, helium and oxygen are more present. Carbon (along with hydrogen and oxygen in the form of water) is what makes up living beings. It's why when people are created, we are are left with evaporated water and charcoal.

Carbon is an extremely flexible element - it can bond with itself in different ways or it can bond with other elements to form a large variety of compounds (For example Carbon Dioxide is a compound formed when one atom of carbon joins with two of oxygen).

Allotropes - Different Structures

The reason why Diamonds and Graphite have such different characteristics is that they are have completely different structures of carbon.

These different structures are called allotropes. It means that the carbon atoms have bonded together differently.

In the case of Diamonds, you can see from the illustration below that its structure is an interwoven mesh and this is why it is such a hard, strong mineral.

On the other hand, you can see from the illustration below that Graphite is made up of sheets of carbon atoms that have little holding them together. So this is why Graphite is so soft and is able to rub off so easily.

The Different Structures of Diamonds and Graphite

Diamonds (left) and Graphite (right)
Diamonds (left) and Graphite (right)
A rough diamond as might be found in nature
A rough diamond as might be found in nature

Why are they different colors?

Humans perceive color by how our brain processes the light bouncing off an object's surface. Trippy but true. Because different surfaces have very different structures, light bounces off them or is absorbed by them highlighting different parts of the light's spectrum. Think of a rainbow - all the colors in it are what makes up light's spectrum of colors. The collection of all colors appears to us as white (so if all colors are reflected back to us), the absence of color in light appears to us as black (so if all color was absorbed by an object).

Diamonds and Graphic are different colors because they have different structure so the light bounces off them differently.

In the case of diamonds, white diamonds are actually clear not white - they are colorless. Like glass, they allow light to travel through them. However, diamonds are often faceted - that is cut so that they have lots of surfaces to reflect light back to the viewer which can give them a whitish appearance.

Carbon absorbs light and thus appears to us as black.

Different colored synthetic diamonds
Different colored synthetic diamonds

Diamonds can come in lots of different colors

Diamonds are not only available colorless but are available in a variety of colors including yellow, brown, blue, green, grey and black. The cause of the different colors can be from impurities (other elements present when the diamond was formed), irradiation or physical deformation of the diamond crystal (which is also known as plastic deformation). In the case of some black diamonds, it can be flaws inside the diamond that absorb light and thereby give it a dark appearance.

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Comments 14 comments

white diamonds 7 years ago

very good diamonds, i love it


Bits-n-Pieces profile image

Bits-n-Pieces 7 years ago

Fascinating topic! I didn't even think of it until I saw your title pop up in the related hubs list of the hub I recently published.

I'm glad I found this hub. Now to check out your other 5 hubs and see what else I can learn today!


GreenMathDr profile image

GreenMathDr 7 years ago

I enjoyed the Hub. I'm partial to topics like this.


ginny 6 years ago

Thanks mate! This helped with my science project!


lifedancer profile image

lifedancer 6 years ago from California

Clear explanation. Black diamonds are popular now. I would advise people not to buy this junk at inflated prices. Black spinel is much better. Don't buy a large black diamond for a solitaire ring. It's too fragile. Go back to this hubber's explanation of the difference between carbon and a diamond. A black diamond is an unfinished diamond full of carbon. Most black diamonds now are irradiated to obtain the blackness, anyway. Information like this is available in my new book, available on www.payloadz,com as a download. Go to "Store" and search the first 2 words of the title. "Enhanced, Plated, Irradiated, and Lab Created: What Jewelry Vendors Don’t Want You to Know"

By Lynn M. Wilde, jewelry and gem enthusiast, with contributions, corrections and the encouragement of Craig Hemphill, certified appraiser © Lynn M Wilde 2010, all rights reserved

It's designed to educate consumers. This is a shameless plug, I know. I just finished the project and am excited.


lifedancer profile image

lifedancer 6 years ago from California

Clear explanation. Black diamonds are popular now. I would advise people not to buy this junk at inflated prices. Black spinel is much better. Don't buy a large black diamond for a solitaire ring. It's too fragile. Go back to this hubber's explanation of the difference between carbon and a diamond. A black diamond is an unfinished diamond full of carbon. Most black diamonds now are irradiated to obtain the blackness, anyway. Information like this is available in my new book, available on www.payloadz,com as a download. Go to "Store" and search the first 2 words of the title. "Enhanced, Plated, Irradiated, and Lab Created: What Jewelry Vendors Don’t Want You to Know"

By Lynn M. Wilde, jewelry and gem enthusiast, with contributions, corrections and the encouragement of Craig Hemphill, certified appraiser © Lynn M Wilde 2010, all rights reserved

It's designed to educate consumers. This is a shameless plug, I know. I just finished the project and am excited.


slc334 profile image

slc334 5 years ago from Canada

This is really neat, and shows how fascinating the world of chemistry is. As far as diamonds go, you should get your girlfriend or wife cubic zirconium, it has a higher refractive index (more sparkle), and it doesn't sublime (diamonds will slowly turn into CO2, it may take hundreds or thousands of years, but the "diamonds are forever" tagline is definitely a lie!).


Pieter 5 years ago

I can understand that a diamond crystal is transparent, and that non-crystalline carbon can be black, but why is a Graphite crystal black ?


chicken 5 years ago

I like diamonds HEHEHEHEHEHEHE


Sachin 4 years ago

BAd explained nothing just they pass the time........


Dev 4 years ago

Nice article on carbon structure of graphite and diamond. If you want top know information about cut,clarity,colour and carat please check http://www.diamondexchange.com.au/


neha 3 years ago

thanks a lot i could keep my name up in the class ,teacher was impressed with me


chandu swamy 2 years ago

diamond hav nice structure and light is pass into diamond and reflects in many to give shining while graphite hav black colour


sudhir kumar 23 months ago

Nice explanation.

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