20 Interesting Facts About Diamonds | Properties & Uses

Over the centuries, diamonds have remained one of the most spectacular gemstones of all time. They appear stunning and mysterious at the same time, and there is a wealth of history and knowledge surrounding diamonds.

The name diamond comes from the ancient Greek adámas, which signifies “I tame” or I overpower”. Although diamonds have been first recognized and mined in India about 6,000 years ago, they were formed before the age of dinosaurs.

Today, diamonds are still recognized as the ultimate symbol of love, which makes them an ideal gift for anniversaries and birthdays. Below, we have gathered some of the most interesting facts about diamonds that will enlighten you about the history, properties, significance, and uses of this popular gem.

Let’s start with some quick facts:

1. Diamonds were first found in India in the 4th century BC. In fact, India was the only source of all the world’s known diamonds until the discovery of diamonds in Brazil in 1726.

2. Diamond is made of pure carbon with its atoms arranged in a crystal. Graphite used in pencils is also made of 100% carbon, just like diamonds. However, graphite crystals are arranged in a different way, making it soft and opaque.

3. Since diamond has the highest number of atoms per unit volume than any other known substances, it is one of the hardest and least compressible materials

4. They are naturally hydrophobic and lipophilic, meaning the surface of a diamond cannot be wet by water but can be easily wet and stuck by oil.

5. The largest gem-quality rough diamond was discovered in Cullinan, South Africa, in January 1905. It weighed 621.35 grams (3,106.75 carats) and estimated to have formed 1.18 billion years ago.

Cullinan diamond (1908) | Credit: Wikimedia 

6. Contrary to common belief, diamonds are not rare in the Earth’s mantle. According to a study, a quadrillion tons of diamonds lie deep below the Earth’s surface.

7. Diamond’s special properties — high dispersion, high electrical resistance, high optical dispersion, low thermal expansion, and chemically inert — make it the world’s most popular gemstone.

8. The use of diamond has grown significantly since World War II. Today, industrial diamonds are mostly used in cutting tools, semiconductor devices, optical components, heat sinks, and heat spreaders. They are also used to cover openings in vacuum chambers, x-ray machines, and lasers.

9. India is the largest exporter of diamonds followed by the United States. However, Russia is believed to be the world’s largest and richest diamond resources. The country produces almost 40 million carats of diamonds every year.

10. Candle Flames Contains Millions Of Tiny Diamonds

A research team at the University of St Andrews revealed that the flickering flame of a candle consists of tiny diamond particles. About 1.5 million diamond nanoparticles are formed every second in a candle flame as it burns.

They discovered both fullerenic particles and diamond nanoparticles in the center of the flame, along with amorphous and graphitic carbon. The diamond particles get converted into carbon dioxide in the process, and currently, there is no way of extracting these nanoparticles.

11. Most Diamonds Form More Than 150 Kilometers Below The Earth’s Surface

Although most diamonds form at depths between 150 and 250 kilometers below the Earth’s surface, some have come from as deep as 800 kilometers.

These gems are formed under extreme temperature and pressure, which cause carbon atoms to crystallize and transform into diamonds. At such depths, temperatures reach up to 1,300 degrees Celsius and pressure goes up to 60 kilobars — 50,000 times that of atmospheric pressure at the Earth’s surface.

12. Diamonds Were Not Always Mined

At present, a large portion of diamonds in the market is mined undersea and underground using high-tech equipment and heavy machinery.

However, a few centuries ago, diamonds were mined alongside or at the bottom of rivers. Some companies still use this mining technique (also called alluvial mining) but it is more often a source of income for individual laborers in regions like South America and Africa.

Moreover, tens of millions of years ago, volcanic eruptions carried diamonds to the Earth’s surface and deposited in igneous rocks. Today, these rocks are called lamproites and kimberlites.

13. Diamonds Are Billions of Years Old

Most natural diamonds are close to 1 billion to 3.3 billion years old, but the oldest ones ever discovered are estimated to be over 4 billion years old.

Usually, the age of a diamond is determined by dating inclusions, assuming it was formed simultaneously with its hosts (minerals or rocks). Advanced spectrometers measure very small differences in the parent and daughter isotopes, revealing the isotopic decay rate. From this data, the age of mineral can be calculated.

14. Diamond Is Very Common In Space

In meteorites, approximately 3% of the carbon is in the form of nanodiamonds. A few of those were formed in stars that lie outside our Solar System.

It rains solid diamond on Neptune and Uranus 

On the ice giant planets Neptune and Uranus, researchers forecast rain storms of solid diamonds. Studies show that diamonds form in the hydrocarbon-rich oceans of slush that swath the planets’ solid cores. Due to intense pressures, these molecules split into atoms of hydrogen and carbon. The latter crystallize to form diamonds.

There is a Star made of diamond  

In 1992, astronomers found a white dwarf star named BPM 37093. The core of the stars is likely one of the largest diamonds in the universe: it is estimated to be over 4,000 kilometers across and weighs nearly 10 billion-trillion-trillion carat.

The star lies 50 light-years from Earth in the constellation Centaurus. It’s so unique that astronomers nicknamed it ‘Lucy’ after The Beatles’ hit song Lucy in the Sky with Diamonds. 

15. Diamonds Have Different Colors

The most popular colored diamond | Hope Diamond | Image credit: Wikimedia  

Not all natural diamonds are colorless. They occur in a variety of colors: white, yellow, red, blue, pink, purple, orange, green, gray, and black.

The color of a diamond is usually affected by structural defects or/and chemical impurities in the crystal lattice. Nitrogen and boron, for example, are the most common impurities found in diamonds. They are responsible for yellow and blue color in diamonds, respectively.

Pure diamonds, on the other hand, are perfectly colorless and transparent. Intense blue, red and pink diamonds are far more expensive than other colored diamonds.

16. Ashes Can Be Turned Into Diamonds

A Switzerland-based company — LONITÉ™ — turns human cremation ashes into diamonds by creating a high-pressure and high-temperature environment in the lab, similar to the natural underground conditions.

To do so, the company requires 200 grams of cremation ashes or 10 grams of human hair. They then run a complicated process to filter and purify the carbon contained in hair or cremation ashes.

Since carbon accounts for approximately 18% of the human body, cremation diamonds are actual diamonds grown in the process.

Read: Physicists Achieve Quantum Teleportation Inside A Diamond

17. Diamond Isn’t The Hardest Substance On Earth

Structure of wurtzite boron nitride

Diamond lost its title of the ‘world’s hardest material‘ to other nanomaterials in the last 2000s. These nanomaterials are:

  • Wurtzite boron nitride: has a similar structure to diamond but is made up of different atoms.
  • Lonsdaleite: made up of carbon atoms just like a diamond, but these atoms are arranged in a different manner.

Computer simulations have shown that wurtzite boron nitride and lonsdaleite can survive 18% and 58% more stress compared to diamonds.

18. Carat Weight Measures A Diamond’s Apparent Size

Carat is used for measuring gemstones and pearls: it’s a unit of mass equal to 200 milligrams. Each carat can be divided into 100 ‘segments’ which allows precise measurements to the hundredth decimal place.

For example, the jeweler may refer to a diamond that weighs 0.35 carats as a ‘thirty-five pointer’. A flawless diamond (with no inclusions) of at least 100 carats (20 grams) is called a paragon.

19. How Many Diamonds Are Mined Each Year?

In 2015, the total worldwide production volume of rough diamonds stood at nearly 35.4 million grams. After 13 years, in 2018, the production stood at 29.4 million grams.

In 2017, the mined rough diamond had a production value of approximately $17.5 billion, while the global diamond jewelry market value was $82 billion.

20. There Is A Place Where You Can Mine Your Own Diamond

Crater of Diamonds State Park 

If you ever find yourself in Arkansas, consider heading for the state park in Pike County. It’s a 37.5-acre plowed field open to the public. It’s the only place in the world where you can dig for diamonds and other gemstones. And if you are lucky enough to find anything, you can keep it (regardless of its value).

In case you are wondering, visitors find over 600 diamonds (of all color and grades) every year. The site became a state park in 1972 and since then more than 29,000 diamonds have been found in the crater.

The most impressive one was found in 1924: it was a white diamond weighing 8.046 g. It was the largest diamond ever discovered in the US. In 1971, the diamond was sold to an anonymous private collector for $150,000.

Read: A Unique Diamond With Another Diamond Moving Freely Inside

21. Biggest Diamond Robbery

One of the largest robberies in history took place in Antwerp, Belgium during the weekend of 15-16 February 2003. Five thieves stole loose diamonds and jewelry valued at over $100 million.

This well-planned robbery is dubbed as ‘heist of the century’. Although thieves were arrested and sentenced to 10 years in prison, most of the gems stolen remain unrecovered.

Written by
Varun Kumar

Varun Kumar is a professional science and technology journalist and a big fan of AI, machines, and space exploration. He received a Master's degree in computer science from Indraprastha University. To find out about his latest projects, feel free to directly email him at [email protected] 

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