Two things that seem like total opposites, at first sight, can sometimes be much more similar than some of you would think. Yes, we’re talking about diamonds and graphite – they fall under that category.
And when two things seem so night-and-day different, nobody would think that they are similar in any way, shape, or form. But that’s not true.
These two naturally occurring minerals are more similar than you would imagine. Not only do they come from the same place and are identical before they undergo a particular process, but they also have similar chemical characteristics.
We know that all of this may sound pretty confusing and that there’s a lot of explaining to do, but that’s why we’re here. What we are about to tell you will completely clear up the air about how diamonds and graphite are similar, and most importantly – what is the difference between diamonds and graphite.
Now, let’s jump straight into the article and see what we have in store for you. Let’s go!
Diamond & Graphite: The Differences
Since most of you reading are here to find out how these two are different, we’ll talk about that first. Then we’ll tell you a little something about how they’re similar – just to help you fully grasp the difference between this crystalline form and the precious, precious rock.
Essentially, both diamonds and graphite are one of the four forms of pure crystalline carbon. The most significant difference from the start is that they’re – well, different forms of it.
The other two forms that we won’t mention any further are carbon nanotubes and fullerenes. So, right from the get-go, we see a distinct separation there.
Diamonds are the most valued and most popular form of carbon, so the majority of you probably knew that diamonds come from carbon. But did you know that graphite does as well?
How is it possible that one thing made from carbon ended up being one of the most expensive things in the world – and the other is used to write on paper? Well, that’s a tough question, but we’re sure you’ll understand by the time you’re done reading this article.
Another way that these two differ is where they are positioned on the Mohs scale of hardness.
As the majority of people know, diamonds are the only naturally occurring substance that is graded a 10 on the Mohs scale which, by the way, is the grade reserved only for the hardest materials.
On the other hand, graphite is rated by a “1” or a “2” on the same scale. Why? Well, the answer is in front of you – graphite is quite a soft material.
Remember how easy it is to snap a pencil in half. Or, for the sake of fair comparisons, imagine how easy it would be to snap only the graphite heart of the pencil without the wood surrounding it. Well, that tells you how soft and brittle graphite is.
There are some other bigger and more complex differences that we’ll get right into – but we wanted to mention the ones that were fairly obvious. That way, you could now focus on the things that are a bit harder to explain and, in turn, understand.
Although we hope we’ll do a great job at it.
First off, let’s look at how both of these are formed under the ground. Then we’ll discuss the differences regarding these processes, as well.
Graphite is formed through the metamorphosis of sediments containing carbonaceous material, the reaction of carbon compounds with hydrothermal solutions or magmatic fluids – or possibly by the crystallization of magmatic carbon.
Well, isn’t that a mouthful?
Anyway, that’s how graphite formation is explained in Britannica – and since the process is a bit complex, we’ll stick to the official explanation.
Now, this is quite different from how diamonds are formed.
Diamonds are found at a depth of approximately 150-200 km below the Earth’s surface. Down there, temperatures average from 900 to 1,300 degrees Celsius and at a pressure of 45 to 60 kilobars – which is around 50,000 times that of atmospheric pressure at the Earth’s surface, by the way.
Under these circumstances, molten lamproite and Kimberlite (commonly known as magma) are also created within the Earth’s upper mantle and expand quite fast. This expansion causes the magma to erupt, pushing it to the Earth’s surface and taking along with it diamond-bearing rocks.
Moving at incredible speeds, the magma takes the path that it can go through with the least resistance, forming a “pipe” to the surface. And as it cools, the magma hardens to form Kimberlite and settles in upward structures, also known as “Kimberlite pipes.”
The so-called Kimberlite pipes are the most significant source of diamonds – but ironically enough, estimates show that only 1 in every 200 Kimberlite pipes contains gem-quality diamonds. The name “Kimberlite” was derived from the South African town of Kimberley, where the first diamonds were found in this type of rock.
As it’s clear from both of these pretty technical explanations of the processes that need to occur for diamonds and graphite to form, they are utterly different.
It’s insane to think about it. Both start out as the same thing – carbon. And yet, somehow, under a set of very specific, intense conditions and extreme processes, they become two very – VERY – different things.
That’s arguably the biggest difference, scientifically speaking, between graphite and diamonds. It might not seem that important to you, but from the technical perspective – that information is crucial.
The natural process that takes place to form either diamonds or graphite from pure carbon is a complex one – and, hands down, the most significant difference between them.
Another difference is the price. As all of you know, diamonds are anything but affordable, and graphite is – well, pretty cheap.
To put it in perspective: A one-carat diamond can be valued between $1,800 and $12,000, depending on the quality and the finish of the diamond. Now, the difference may shock you, but according to market research, a metric ton of graphite is valued at around $690 dollars.
Some of you might not have seen this big of a difference coming – but just remember how much does a graphite pencil cost.
Around $1 or $2, right? Well, the amount of graphite that goes inside your average pencil would be worth a staggering 2000 times more if it was a diamond heart.
Given the fact that there are only limited amounts of these materials, some of you might pose a valid question of the prices rising. Well, that’s not going to happen anytime soon – especially when we’re talking about graphite.
Last year, Turkey ranked as the country with the most reserves of graphite that were around 90 million metric tons. China has around 73 million, and Brazil has around 70 million metric tons of graphite in reserves. That might put into perspective how widely available this material is, especially when compared to a diamond.
Now let’s take a look at some reserves countries have when it comes to diamonds.
Russia is the country with the biggest reserves of diamonds in the world, with over 650 million carats in their reserves. The second is Botswana that has less than half of what Russia owns – and that’s still an impressive 310 million carats.
Also, keep in mind that a carat is a metric unit that’s equal to 200 milligrams. When you look at this data, you can clearly see that the difference in the reserves is also one of the largest ones – literally.
And the rarity of a particular material plays a huge role in determining its price and value. As you probably know, scarcity is one of the most significant factors for anything naturally formed on – or in – the Earth, such as gas, gold, and diamonds.
Diamond & Graphite: The Similarities
Now let’s briefly look at some similarities that diamonds and graphite share and see how they’re similar. You already know how they’re different.
The first thing that binds these two together is the fact that they both originate, or are a derivate, of pure carbon. The only difference is those processes that we talked about earlier.
So, if carbon undergoes one process, it will become a diamond. And if it undergoes a different process – it becomes graphite.
It’s mind-blowing. Some might think that this is where all the similarities between diamonds and graphite end – but that’s not correct.
The majority of the similarities we are about to discuss are of chemical nature, so bear with us for a moment.
First of all – and the most important for this topic – are the covalent bonds seen in diamonds and graphite. They’re virtually the same for both materials; carbon atoms share valence electrons, electrons in the outermost electron shell, with other carbon atoms in the structure.
That may all seem quite confusing, but the fact is that, from a chemical perspective, this is quite important to understand – and keep in mind as we move on.
These covalent bonds make diamonds and graphite very similar, and they cannot be overlooked just because the topic seems complicated.
Another chemical similarity between those two is the melting point.
The melting point is the point of high temperature where a specific material starts to change its form from solid to liquid.
Both diamonds and graphite have extremely high melting points, and they’re hard to turn into a liquid state. When you try to burn the heart of a graphite pencil, you’ll see that you’ll just burn the inside and that it will cool off in no time.
The same exact thing happens with a diamond – and for the same reason. The reason is that the process that both of these materials have to undergo to form from carbon includes high temperatures – much higher than anything you could produce.
We’ve talked a lot about how diamonds and graphite are different, then we’ve talked about how they are similar – but why does it even matter?
Well, it’s vital that we’re aware of how two utterly different materials can be similar and different at the same time. They share some characteristics – and yet, they are completely different at the end of the day.
One is used in jewelry and high-grade industrial machinery, and the other one is mainly used to write on paper.
Although these two materials are made from carbon, other than chemistry, they are completely different. From the way they are formed deep beneath the Earth to their primary use – they are two totally separate things.
And yet, in a sense, they are not.
It’s fascinating that two things that are so different can come from the same thing – carbon – but become two completely distinct and incomparable things.
We hope that we cleared up the air around the question of what is the difference between diamonds and graphite and helped you understand where they differ and how they’re similar.
Also, we hope you enjoyed reading!
Read Also: Why Does Diamond Not Turn Into Graphite?