A Complete Guide to Diamonds (Heera)

This article serves as part of an ongoing series of profiles on the different varieties of precious & semi-precious gemstones. To view the entire list, click here.

Diamonds, the exquisite gems that have enchanted mankind for centuries, hold a place of unmatched fascination and desire. These captivating gemstones have enthralled humanity, earning their place as the pinnacle of luxury and timeless beauty. Admired and sought-after by connoisseurs worldwide, diamonds have become an iconic symbol of prestige and enduring elegance.

Fun fact: While diamonds on Earth are undeniably rare, they’re also found in outer space, believe it or not. Specifically, mankind has found proof of literal rains of diamonds on Neptune and Uranus, and in 2004, a planet named “Lucy” (after the legendary Beatles song) was found to have crystallised into a diamond – making it a literal diamond planet!

From the depths of the Earth to the vast expanse of the universe, diamonds truly are, forever. In this gemstone profile, we delve into the captivating world of diamonds, exploring their formation, origins, inclusions, common treatments, quality factors and much more, unravelling the mysteries that make diamonds truly remarkable.

1. Diamonds - Formation & Occurrence

Diamonds are formed through a remarkable process that unfolds deep within the Earth's mantle over millions of years. These gemstones are composed of carbon and originate from carbon-rich materials, undergoing tremendous pressure and temperature under specific geological conditions. Natural diamonds can be as old as 1 billion to 3.5 billion years – about half as old as our planet itself. The majority of them take shape at depths between 150 km - 250 km within the Earth's mantle. 

Diamonds are primarily formed in 2 types of environments: the Earth's mantle and subduction zones:

• The Earth’s Mantle: Nearly all diamonds found in diamond mines are believed to have originated in the upper mantle of the Earth. Within the mantle, extreme heat and pressure create an ideal setting for diamond formation. In this extreme environment, carbon atoms bond together, adopting a crystalline structure that gives rise to the formation of diamond crystals. These diamond crystals are then transported to the Earth's surface through powerful volcanic eruptions. Volcanic rocks such as kimberlite and lamproite play a crucial role in this remarkable ascent - these rocks act as conduits, forcefully propelling diamonds as they surge upwards during volcanic eruptions. Upon reaching the surface, the molten volcanic materials gradually cool and solidify, often leaving behind valuable diamond deposits or creating diamond-bearing geological formations.

Diamond formation in the Earth’s mantle (Source: Geology.com)

• Subduction Zones: These also contribute to diamond formation. When tectonic plates collide, one plate is forced beneath another, descending into the mantle. Within the intense heat and pressure of subduction zones, carbon materials undergo transformations, leading to the creation of diamonds. Over time, geological forces uplift these diamond-bearing rocks to the surface through processes like mountain-building or erosion. The occurrence of rocks that have undergone the process of subduction and subsequent return is exceptionally uncommon. These rocks are incredibly rare, and very seldom are commercially viable diamonds discovered within them.

Diamond formation in subduction zones (Source: Geology.com)

While diamonds are considered rare and highly valued, they are not as scarce as coloured gemstones like rubies, sapphires and emeralds. Despite their relative abundance, the diamond mining and manufacturing industry remains concentrated in the hands of a few major companies, including Alrosa, DeBeers, Rio Tinto, and Anglo-American, resulting in an oligopolistic market.

This market dominance is reflected in the geographical distribution of diamond reserves and production, with Russia leading as the world's largest and richest producer of diamonds. Botswana closely follows as the second-largest global producer, while Canada, the Democratic Republic of Congo, South Africa, Australia, Angola, and Zimbabwe make significant contributions to the diamond industry.

2. Where Are Diamonds Found?

Diamonds are unearthed in over 30 countries around the world. The following countries, however, stand out as the primary sources of diamonds in the global industry:

• Russia: As the world's largest diamond producer, Russia holds a prominent position in the global diamond market with an output of about 39 million carats in 2021. The majority of its diamond production originates from the Yakutia region in Siberia. ALROSA, the state-owned mining company, exerts significant influence over the industry, operating numerous mines in the area. Notably, the Aikhal mine, known as stands as one of the world's largest diamond mines and is located in Yakutia, Russia.
• Botswana: Despite its relatively small size, Botswana ranks as the world's 2nd largest producer of diamonds. It is also recognized as a significant source of conflict-free diamonds. Botswana's diamond production is greatly influenced by the Orapa and Jwaneng mines. Notably, the Orapa mine holds the distinction of being the world's largest diamond mine in terms of area, while Jwaneng stands as the richest mine globally, renowned for yielding high-quality diamonds. Meghan Markle’s engagement ring which boasts a diamond from Botswana, attests to the reputation of the country's diamonds.

Meghan Markle’s Botswana diamond ring

• Canada: Canadian diamonds hold a distinguished reputation due to the country's commitment to exceptional environmental standards and conflict-free mining practices. The Ekati mine, one of the country's earliest, stands as an exemplar of this commitment, along with the Diavik mine. The stringent regulations and ethical considerations associated with Canadian diamond mining have drawn the attention of conscious consumers, who appreciate their exceptional quality alongside their ethical origins.
• South Africa: With a storied history in diamond mining, South Africa remains a noteworthy contributor to the global diamond trade. The country's diamond mines like the Cullinan mine have yielded extraordinary gems, including the legendary Cullinan diamond, the largest diamond ever discovered, and the Oppenheimer Blue, which attained the remarkable distinction of being the most expensive jewel ever sold at auction in 2016. This mine also stands out as a valuable producer of blue diamonds.

The Cullinan rough diamond - weighing 3,106 carats (Source: Wikipedia)

While these countries play pivotal roles in the diamond production landscape, it is essential to acknowledge that diamonds can also be found in other regions worldwide. Notable diamond-producing countries like Australia, Angola, and Zimbabwe also contribute to the captivating diversity and allure of this extraordinary gemstone.

3. The Colours of Diamonds

Diamonds come in a remarkable array of colours that go beyond traditional white diamonds. While white diamonds have long been treasured for their classic beauty and scintillating brilliance, coloured diamonds captivate with their extraordinary hues, each telling a unique story.

Before delving into the colours of diamonds, it's essential to understand the grading scale used for white diamonds. The Gemological Institute of America (GIA) has developed a globally accepted, comprehensive colour grading scale from D to Z to assess the absence of colour in diamonds. Diamonds in the D to F range are considered colourless, while those in the G to J range are nearly colourless. As we move down the scale from K to Z, diamonds gradually exhibit increasing shades of yellow or brown.

Colour grading of white diamonds (Source: GIA)

Beyond this D - Z colour range for white diamonds, lies a realm of captivating fancy-coloured diamonds. These diamonds exhibit a mesmerizing array of hues, with yellow and brown being the most common, followed by shades of pink and blue. Exceptionally rare colours include red, green, purple, and orange. The charm of these colours is a result of specific chemical elements trapped during the diamond's formation. For instance, the yellow colour in diamonds arises from the presence of nitrogen atoms and a blue colour is the result of boron. These coloured diamonds command significantly higher prices than their white counterparts, as they’re exceptionally rare and elusive in nature.

Diamonds can also occur in rarer shades of yellow, blue, pink, etc.

4. Common Inclusions in Diamonds

Inclusions, formed under extreme pressure and heat, are an intrinsic part of diamond formation, providing valuable insights into a diamond's age, formation and quality. These internal characteristics not only help in distinguishing between synthetic and natural diamonds but also contribute to a diamond’s overall quality. While flawless diamonds without inclusions are rare, most inclusions are not readily visible to the naked eye and require high magnification for observation.

Pinpoint inclusions are the most common ones found in diamonds. These tiny black or white dots represent entrapped minerals or crystals, discernible on the diamond's surface. Feathers are also common and refer to small cracks or fractures. Depending on the viewing angle, feather inclusions may appear transparent or exhibit a whitish feather-like appearance when reflecting light. Diamonds may also contain crystal inclusions. They consist of small diamond fragments or trapped mineral crystals. Finally, cloud inclusions are frequently observed in diamonds, showcasing a cloud-like formation with closely clustered pinpoints or crystals.

Feather inclusion in a Diamond (Source: GIA)

While inclusions are essential in determining the clarity of a diamond, they do more than just indicate its purity. In fact, these unique internal characteristics can add a touch of individuality and charm to each stone, making it truly one of a kind.

5. Common Treatments & Enhancements of Diamonds

Only a small portion of gem-quality diamonds undergo treatments, primarily to improve clarity or to enhance colour.

• Clarity Enhancement: These techniques aim to minimize the visibility of inclusions. One such method is Laser Drilling, where a tiny hole is created using lasers to reach and lighten a dark inclusion. The drill hole created during laser drilling is a permanent alteration and cannot be reversed. Fracture filling is another common treatment, involving the infusion of a glass-like substance into fractures to enhance the diamond's appearance. However, fracture-filled diamonds may experience a slight decrease in colour and can develop cloudiness over time. This treatment is particularly effective in filling clear feather-type inclusions.
• Colour Enhancement: These treatments are employed to modify the hue of diamonds. One such process is High Pressure, High Temperature (HPHT), which can be used to make slightly brownish diamonds appear whiter. Additionally, slightly tinted diamonds can undergo HPHT treatment to enrich their colour, resulting in distinct tones such as pink or blue.

It's worth noting that a colour-enhanced diamond is considered to have less value compared to a natural diamond, as the treatment involved is not natural. While these treatments can enhance certain aspects of diamonds, it is crucial for buyers to be aware of the treatments, and for sellers to disclose these treatments

Diamonds (Heera) - A Quick Snapshot

6. Evaluating the Quality of a Diamond

When evaluating the quality of a diamond, one cannot go wrong with the 4Cs of quality: Colour, Clarity, Cut & Carat weight.

• Colour: The colour of a diamond is graded on a scale ranging from D (colourless) to Z (light yellow or brown). The most valuable and sought-after diamonds exhibit a lack of colour, appearing white or colourless. Diamonds in the D-F range are considered ideal, boasting exceptional whiteness and brilliance. However, near colourless diamonds graded G-H-I-J offer excellent value, as the naked eye cannot readily discern the subtle differences in colour between these grades.
• Clarity: Clarity refers to the presence or absence of internal characteristics called inclusions. Clarity is graded on a scale from Internally Flawless (IF - no inclusions visible under 10x magnification) to Included (inclusions visible to the naked eye). Diamonds with higher clarity grades are considered more valuable, and flawless diamonds are exceedingly rare. For instance, a diamond with a clarity grade of VVS1 (Very Very Slightly Included) or higher would be highly prized for its exceptional clarity. In comparison, a VS2 (Very Slightly Included 2) diamond may have inclusions that are not visible to the naked eye either and will require magnification.
• Cut: The cut of a diamond refers to its proportions, symmetry, and polish, which determine how well the diamond reflects light. A well-cut diamond exhibits brightness (white light reflection), fire (refraction and flashing of vibrant colours), and scintillation (sparkle and brilliance).
• Carat Weight: The carat refers to the weight of the diamond. A higher carat weight generally indicates a larger diamond and is often associated with increased value. Diamonds ranging from 30 cents to 1 carat are classified as standard in size, while those exceeding 1.5 or 2 carats are deemed exceptionally large. It is at this point that the price of a diamond experiences an exponential increase, reflecting its enhanced rarity and desirability.

Neither of these factors can be considered in isolation, and gemmologists need to assess all these factors in tandem to evaluate a diamond's overall quality.

7. How Much Do Diamonds Cost?

The cost of diamonds varies significantly depending on the factors mentioned above. Larger diamonds generally have a higher price due to their rarity and demand. Colourless diamonds with higher clarity grades also tend to be more expensive. Additionally, well-cut diamonds that maximize brilliance and sparkle may also come with a higher price tag.

In the diamond industry, pricing and market trends are closely monitored and analysed. One notable resource for diamond pricing information is the Diamond Rapaport price sheet, an industry standard established by Martin Rapaport.

This comprehensive report is updated weekly and serves as a vital resource for jewellers, diamond traders, and industry professionals. It provides valuable insights into the pricing of individual diamonds, considering factors such as size, colour, and clarity. It serves as a benchmark for setting consumer prices and reflects the dynamic developments in the global diamond market. As an indispensable reference, it not only educates diamond traders and sellers about current pricing trends but also enables diamond retailers to adjust their prices in line with the ever-evolving market conditions.

The diamond Rapport - detailing prices of a diamond in a matrix of colour, clarity, and carat weights

8. Diamonds in Astrology

In astrology, diamonds are often connected with the planet Venus, which symbolizes beauty, love, and harmony. Diamonds are also the birthstone for April and are associated with the Zodiac signs Virgo and Libra.

Historically, Indian scholars wrote of the supernatural powers attributed to diamonds, believing they possessed the ability to ward off evil. Ancient Romans and Greeks also held fascinating beliefs about diamonds - considering them as tears of the gods or fragments that had fallen from the stars. Ancient Roman literature describes Cupid's arrows as being tipped with diamonds, highlighting the association of diamonds with love and romance. These rich cultural beliefs and associations have contributed to the enduring symbolism and mystique surrounding diamonds in the realm of astrology and beyond.

Diamonds (Heera) in Astrology

In general, diamonds are believed to offer a range of benefits in astrology:

• Enhancing physical health: Diamonds are associated with promoting vitality and overall well-being. As gemstones connected with the planet Venus, diamonds are believed to enhance energy levels, alleviate physical discomforts and contribute to a sense of physical rejuvenation.
• Attracting prosperity: Diamonds are believed to attract wealth and opportunities for material prosperity. The association with the planet Venus, representing material abundance and luxury, further reinforces the connection between diamonds and wealth. Wearing diamonds is thought to invite career growth and financial well-being.
• Fostering love: Diamonds symbolize deep and lasting love and are often associated with commitment and devotion. Wearing diamonds is believed to strengthen romantic relationships, fostering emotional connection and intimacy. Diamonds are thought to enhance passion and promote harmonious communication and understanding in relationships.
• Fuelling creativity: Diamonds are believed to ignite creative inspiration and encourage unique ideas. Diamonds are often associated with clarity of thought and mental focus, helping individuals tap into their creative potential.