How Are Diamonds Made?

How Are Diamonds Made?

  • September 18, 2019
  • In Diamonds
  • By Amy Huang

Have you ever thought, “How are diamonds made?” If so, we’ve got the answer for you!

Diamonds have been en vogue for hundreds of years, but they’ve been in the earth much longer. The first diamonds were formed deep within the earth’s upper mantle about 3 billion years ago (just beneath the Earth’s crust). Four basic ingredients make up the recipe of how diamonds are made: carbon, pressure, heat and time. The upper mantle is ideal for growing diamond crystals. These crystals are formed when carbon atoms bond. It’s this bond that makes diamonds such a hard material. A one-carat diamond has billions of carbon atoms.

So, how are diamonds made? It’s a slow process. The youngest diamond was at least 900 million years old when dinosaurs went extinct.

The upper mantle is also responsible for the movement of tectonic plates. Hundreds of millions of years ago, these plates caused volcanic eruptions which brought diamonds to Earth’s surface. Humans discovered them about 2500 years ago.

Diamonds are pure carbon. Interestingly, carbon makes one of the hardest materials in the world (diamonds) as well as one of the softest (graphite). The latter is formed similarly to diamonds, the difference is in how the carbon atoms are arranged. The Mohs hardness scale, invented by a German mineralogist in 1812, measures a mineral’s resistance to being scratched. Diamonds rank a ten out of ten as the hardest mineral and graphite ranks at the opposite end of the scale (one to two).

What are diamonds made of that give them such vibrant colors? When trace minerals and other infiltrators come to the carbon-diamond party, vibrant colors happen. It’s rare in nature, happening only one in every ten thousand times. Nitrogen makes diamonds orange and yellow, boron makes blue and gray diamonds, and hydrogen makes diamonds purple. Pink and brown diamonds occur while still deep in the earth when distortions in the crystal lattice absorb green light that reflects a pink hue.

What are Diamonds Made of?

How are diamonds made? If Mother Nature had a recipe card, it would read: Take carbon atoms and place them in the earth’s mantle about 100 miles down, heat them to at least 2200 degrees under 727,000 pounds of pressure per square inch. Set timer for one billion years. When done, let cool completely before cutting and serving.

The carbon that makes up diamonds is the same element found in all living things. Carbon is the fourth most abundant element in the universe and the second most abundant element in the human body.

The sixteenth-century French scientist Antoine Lavoisier named carbon after doing an experiment that burned a diamond until all that was left was carbon dioxide. He concluded that carbon mixed with oxygen formed into carbon dioxide, the same thing that burning coal produced. Thus, diamonds and coal were made out of the same element: carbon.

How to Get a Diamond Naturally

It’s important when purchasing diamonds to understand the 4Cs (carat weight, color grade, clarity grade, cut grade). When looking at a diamond, don’t get caught up with the price or carat weight and forget about what makes or breaks a diamond: an excellent cut. When looking at a diamond sans an independent grading report, ask to look at another diamond alongside it with a report (and the same 4Cs). The latter will help you assess if the former was graded too liberally.

When selecting a jeweler, it’s not only important how long a company has been in business, but also how long the owner has been in the industry. Education is also important. Did the owner just take a two week diamond course with GIA before opening up shop or did they go all the way?

How to get a diamond that fits your sense of style and budget requires a learned jeweler. If you ask “How is a diamond formed?” your jeweler should be more than happy to answer that. The owner of Diamonds Forever San Diego will always be happy to answer your questions.

What is a Lab-Created Diamond?

So, what are diamonds made of in the lab? The same recipe that created natural diamonds is mimicked. It’s akin to natural pearls and cultured pearls, while the former happens by chance, the latter is helped along by humans.

So, what is a lab-created diamond? There are two processes. The first involves high-pressure and high temperature and the other involves chemical vapor disposition. The first method plants a diamond seed into high heat and pressure. As the carbon melts it starts to form diamond crystals around the starter seed. It’s then cooled to form a pure carbon diamond. The second method places a diamond seed into a sealed heated chamber that is then filled with a carbon-rich gas. Lasers are then used to ionize the gas into plasma. As the molecules break down, pure carbon slowly starts to crystallize around the diamond seed.

The result is a diamond that has all the same physical properties of one that took a billion years to make.

Blue diamonds are very rare in nature and can cost hundreds of thousands of dollars per carat. A lab-created blue diamond costs ten-percent of that.

How is a diamond formed in the lab to have color? Orange diamonds happen when a solvent used in the lab-growing process is trapped inside the structure of the diamond with the nitrogen. Pink lab-created diamonds get their color after the stone is grown by showering the stone with electrons and neutrons before being heated.

Chocolate diamonds are simply a deep rich brown or cognac color. How are chocolate diamonds made in a lab? Simply put, by the introduction of nitrogen and nickel.

Frequently Asked Questions

What is Harder Than a Diamond?

Diamonds are regarded as the hardest natural material on Earth. So, what is harder than a diamond? Not much. While science has discovered (Longsdaleite) and created (Wurtzite Boron Nitride) substances harder than diamonds, they aren’t nearly as abundant or have the same staying power.

How are Chocolate Diamonds Made?

How are diamonds made to have that alluring chocolate color? Brown diamonds have a more compressed internal structure than colorless diamonds. It’s thought that more pressure was used when nature formed brown diamonds. Graining is seen under magnification far more than what is seen in colorless diamonds.

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