Diamonds are forever – whether made in a lab or mined from the earth – by Joshua Wilhide and William LaCourse (The Conservation – December 12, 2018)

https://theconversation.com/

It’s diamond season. Almost 40 percent of American engagements happen between Thanksgiving and Valentine’s Day, with Christmas the most popular day to pop the question – and hand over a sparkly piece of ice. Jewelry stores do at least double their usual monthly sales in December.

Since at least the late 1800s, with the discovery of huge diamond mines in South Africa, people have treasured these dazzling gems. The beauty and splendor of diamonds goes well beyond the surface. Like a diamond hunter digging in an underground mine, one must look deeper to their atomic characteristics to understand what sets these stones apart – and what makes them valuable not just for romantics but also for scientists.

When mined from the earth, diamonds look like cloudy rocks before they’re cut and polished. Their chemical nature and structure were unknown for centuries. It was Isaac Newton’s experiments in the 1600s that first suggested diamonds are made up of the fourth-most abundant element, carbon.

People doubted Newton’s discovery, which is understandable considering how different diamonds look from other common forms of carbon, like the graphite in pencils or the ash left over in a wood-burning fireplace. But in 1797, English scientist Smithson Tennant confirmed the composition of diamonds.

It turns out that carbon takes two common forms that have crystalline structures on the atomic level. Graphite is a repeating two-dimensional, honeycomb-like shape, with layers stacking on top of each other. Alternatively, carbon can form a repeating three-dimensional shape, a tetrahedron – and that’s your diamond.

For the rest of this article: https://theconversation.com/diamonds-are-forever-whether-made-in-a-lab-or-mined-from-the-earth-106665

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