Diamonds are precious minerals coveted by all. Part of its appeal is that it’s not common and this is because it takes an incredible amount of pressure to form a diamond — 725,000 pounds per square inch approximately. This high pressure is usually found deep within the Earth’s mantle, where temperatures are also incredibly high. Here’s what you need to know.
How Much Pressure Does it Take to Make a Diamond?
The answer to the question how much pressure does it take to make a diamond is 725,000 pounds per square inch. So, how does all that pressure turn carbon into diamonds? Well, it actually has to do with the crystal structure of carbon. When carbon is under intense pressure, its crystal structure changes and becomes more closely packed together.
Creating a diamond requires two things: extreme pressure and extreme heat. These conditions are found deep within the Earth’s mantle, about 100 miles below the surface. The mantle is made up of hot rock that is under tremendous pressure. As this hot rock rises toward the surface, it begins to cool.
The process of making diamonds in a controlled process is called diamond synthesis. It involves subjecting carbon to extremely high pressures and temperatures in order to change its crystal structure and turn it into a diamond.
The most common method of diamond synthesis is called chemical vapor deposition, or CVD. This process involves using a gas like methane or carbon dioxide, which is broken down into its constituent atoms by a plasma torch. These atoms are then deposited onto a surface, where they bond together and grow into a diamond crystal.
CVD is the most commonly used method of diamond synthesis, but it’s not the only one. Another popular method is called high pressure high temperature, or HPHT. This process involves subjecting carbon to incredibly high pressures and temperatures in order to change its crystal structure and turn it into a diamond. HPHT is typically used to create larger diamonds, like those used in engagement rings.
Are Diamonds the Hardest Substance on Earth?
Yes, diamonds are the hardest known naturally occurring substance on Earth. This hardness is measured in Mohs hardness scale. On this scale, diamonds are assigned a value of 10 — the highest value possible.
To illustrate how hard a diamond is, consider that the pressure at the center of the Earth is about 3.5 million times atmospheric pressure. It would take a diamond anvil with a pressure of approximately 60 GPa (gigapascals) to scratch another diamond.
The process for measuring a diamond with the Mohs hardness scale begins with an identification of the scratch resistance of an unknown diamond. The Mohs hardness scale is then referenced to find a diamond that can scratch the unknown diamond. This process is repeated until the hardest known substance, diamond, is reached.
The value assigned to diamonds on the Mohs hardness scale is due to the extremely strong covalent bonds that hold carbon atoms together in the lattice structure of a diamond. These bonds are so strong that it takes an enormous amount of pressure to break them.
Here’s the Mohs measurement of diamonds compared to other gems and minerals for perspective:
| Gems and Minerals | Mohs Hardness |
|---|---|
| Talc | 1 |
| Gypsum | 2 |
| Calcite | 3 |
| Fluorite | 4 |
| Apatite | 5 |
| Orthoclase feldspar | 6 |
| Quartz | 7 |
| Topaz | 8 |
| Corundum (sapphire and ruby) | 9 |
| Diamond | 10 |
What Can Cut Diamond?
Diamonds are cut with professional diamond saws and cleavers. For large diamonds, a motorized saw is used to make the initial cut while a hand held saw is used for smaller stones.
The amount of pressure required to cut a diamond depends on the hardness of the stone. It can take anywhere from 10,000 to 60,000 pounds per square inch (psi) of pressure to cut it. Softer diamonds can be cut with less pressure than harder ones. However, all diamonds require a significant amount of force to cut through. For example, it takes about 62,000 pounds per square inch (422,000 kPa) of pressure to cut a 1 carat (200 mg) diamond.
Yet another way is with lasers. A laser is aimed at a spot on the diamond where the cut is desired. Then the laser heats up the diamond and causes it to crack.
How to Break A Diamond?
To break a diamond, you need to hit it with an object hard enough to create a crack or chip. The harder the object you use, the easier it is to break the diamond. The most common is using a hammer and chisel, but diamonds can also be broken lasers as explained above, or extreme heat.
Hammer and Chisel
With a hammer, you can exert up to 60,000 pounds per square inch (psi). First, find a spot on the diamond where you want to make the break. Place the chisel on the diamond at that spot and hit it with the hammer.
It may take a few hits to get through the diamond. If you hit it too slowly, the diamond will just absorb the energy and not break, but hitting it too hard can cause the diamond to shatter. You should aim for the middle of the diamond so that it breaks evenly.
Extreme Heat
One other way to break a diamond is with extreme heat. This can be done at home, but it’s very dangerous and should only be attempted if you are experienced with working with fire. First, you will need to get a piece of charcoal that is big enough to fit the diamond. Then, you will need to light the charcoal on fire and wait for it to get white hot. Once it is white hot, place the diamond in the middle of the charcoal and wait for it to crack. This could take a few minutes or even an hour, so be patient.
Final words
In conclusion, the pressure needed to create a diamond is very high. The process requires extreme heat and pressure to carbon atoms in order to form a crystalline structure. This is why diamonds are found deep within the Earth’s mantle, where these conditions exist. It’s also why man-made diamonds are made in controlled environments. Thanks for reading! Don’t hesitate to share and comment.
