Us humans have always had a soft spot for diamonds. Ancient civilizations prized them so much that they believed trying to change them in any way would disrupt their innate properties. In fact, they are not only used in the jewellery industry; their hardness is also prized in oil drilling, special scalpels for cutting, and tool manufacturing. But what exactly makes them so special?
Most diamonds are thought to be formed from intense heat and pressure in a layer called the mantle, just below the crust. In fact, the specific area within the mantle that diamonds are formed in is so unique that it is called the diamond stability zone! The heat and pressure in this zone forces each carbon atom to bond with four other carbon atoms. Graphite, or the “lead” in your pencils, is also made from carbon atoms bonded to other carbon atoms. But instead of one atom being bonded to four others, one is only bonded to three others. Because of this, graphite can come off in sheets (see diagram below) onto your paper, helping you write!
Source: Wikimedia Commons
Some other possible methods for diamond formation include subduction zones, meteoroid impact sites, and some could even be formed in space as well! Diamonds can also be made synthetically, with conditions that simulate what happens under the Earth’s surface. The process takes only a few weeks rather than a few billions of years. And the few billion years doesn’t even include the time needed to get them to the surface! Diamonds formed in the Earth must come to the surface via volcanic activity, since this is how rock in the upper mantle ever reaches the crust.
Diamonds are mostly mined in India and Africa. Unfortunately, those who work in diamond mines are usually underpaid, have bad working conditions, and have a high risk of injury. Mining also pollutes the environment and decreases wild habitat. Companies have tried to improve their mining practices, though these remain problems in the industry. This is another reason for why people use synthetic diamonds; they remain a more ethical and eco-friendly choice.
After mining, diamonds are sorted by properties such as size, color, brilliance, etc, before being cut into pieces for products. Hold on, Wednesday Science, diamonds don’t appear in that brilliant shape that we love in nature? Nope! They have to be cut in that way in order to get that shape! Diamonds are cut by cleaving (separating into smaller pieces), sawing, or laser cutting to get smaller, workable pieces. A process called bruting is used to grind away at the edges for an outline shape, and they are finally faceted to polish the exterior. What a process!
Diamonds are very bright because they have a high refractive index, meaning that the speed of light through them is much slower than when light travels through a vacuum. They also reflect a lot of light back at the viewer, making them seem even brighter. That shape we love? Those make diamonds seem even brighter because of the way light is internally reflected in them!
Now you know what makes diamonds so special, and why they are deemed so precious in society. You also know what all they’ve been through, from their rough and tough formation, to their lavish uses. So the next time you see a diamond, remember to appreciate its story and what it’s been through to get there!
Post By: Roshni P. M.
Photo credits: Unsplash, Bulbul Ahmed, https://unsplash.com/photos/ZLTLEaCCYh0
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