Introduction to Diamonds: Origin, Properties and Formation
Diamonds are among the most fascinating and sought-after minerals in the world. They have exceptional physical and chemical properties. As a result, they are used in science, in the jewellery industry and in the investment sector.
History and culture
Diamonds already played an important role in trade and culture in ancient times in India, between around 1500 and 500 BC. Until the 18th century, India was the main source of these precious stones. The word ‘diamond’ comes from the Greek ‘adamas’, which means ‘invincible’ or ‘very resistant’. Strangely enough, diamonds were unknown in classical Greece (ca. 510-323 BC); the term was only used in philosophical contexts.
Historically, the largest diamonds were symbols of power and belonged to kings & empires. Today, they are not just for aristocrats, but are also highly prized by celebrities, investors & jewellery lovers. Especially in uncertain economic times, diamonds are considered a valuable form of investment.
Physical and chemical properties
As the hardest natural mineral, diamonds consist exclusively of carbon, which is crystallised in the cubic crystal system. This special hardness has given rise to a famous slogan: ‘A Diamond Is Forever’. Due to their robustness and optical properties, they are used in many industrial applications such as cutting, drilling and optics.
The high atomic density slows down the light that passes through the diamond. This creates the remarkable play of light or ‘fire’. The refractive index of a diamond is around 2.42, making it one of the most brilliant gemstones.
Variety of colours
Although colourless diamonds are the best known, they also come in many colours! These so-called ‘fancy’ diamonds are rare and extremely valuable. Transparent diamonds can take on all the colours of the rainbow - from red to violet and many mixtures in between. There are also white (milky) and black (opaque) varieties.
Formation and occurrence
Diamonds provide insights into processes deep within the earth. Most are formed around 140 to 200 km below the earth's surface in the lithospheric mantle under extreme conditions, where carbon crystallises to form a diamond. It is assumed that the carbon originally came from sediments that were sucked in from the surface.
Remarkably, there are also ‘super-deep’ diamonds that come from depths of over 600 kilometres! These continue to fascinate geologists.
Diamonds also reach the earth's surface through rapidly rising kimberlite magma. Whilst kimberlite is not the parent rock of the diamond, it transports it upwards. Many of these gemstones are very old - some from the Ekati mine in Canada have been estimated to be around 3.5 billion years old, as have those from Siberia and Zimbabwe.
Today's diamond mining
Diamonds are found either in primary deposits (in kimberlite rock) or in secondary deposits. The latter are formed by erosion of the parent rock, which allows the diamonds to accumulate in river beds or elsewhere.
In recent decades, synthetic diamonds have gained in importance and are increasingly being used in jewellery. Nevertheless, it is important to clearly differentiate between synthetic and natural variants, as only natural diamonds may bear the term ‘diamond’ on their own. Treatments to improve appearance or colour must also be disclosed.
Diamonds as an investment
During times of economic uncertainty and inflation, diamonds offer a stable investment. They are a sensible addition to traditional investments such as gold and not only offer aesthetics and rarity, but are also an excellent way to protect and increase wealth.
History and culture
Diamonds already played an important role in trade and culture in ancient times in India, between around 1500 and 500 BC. Until the 18th century, India was the main source of these precious stones. The word ‘diamond’ comes from the Greek ‘adamas’, which means ‘invincible’ or ‘very resistant’. Strangely enough, diamonds were unknown in classical Greece (ca. 510-323 BC); the term was only used in philosophical contexts.
Historically, the largest diamonds were symbols of power and belonged to kings & empires. Today, they are not just for aristocrats, but are also highly prized by celebrities, investors & jewellery lovers. Especially in uncertain economic times, diamonds are considered a valuable form of investment.
Physical and chemical properties
As the hardest natural mineral, diamonds consist exclusively of carbon, which is crystallised in the cubic crystal system. This special hardness has given rise to a famous slogan: ‘A Diamond Is Forever’. Due to their robustness and optical properties, they are used in many industrial applications such as cutting, drilling and optics.
The high atomic density slows down the light that passes through the diamond. This creates the remarkable play of light or ‘fire’. The refractive index of a diamond is around 2.42, making it one of the most brilliant gemstones.
Variety of colours
Although colourless diamonds are the best known, they also come in many colours! These so-called ‘fancy’ diamonds are rare and extremely valuable. Transparent diamonds can take on all the colours of the rainbow - from red to violet and many mixtures in between. There are also white (milky) and black (opaque) varieties.
Formation and occurrence
Diamonds provide insights into processes deep within the earth. Most are formed around 140 to 200 km below the earth's surface in the lithospheric mantle under extreme conditions, where carbon crystallises to form a diamond. It is assumed that the carbon originally came from sediments that were sucked in from the surface.
Remarkably, there are also ‘super-deep’ diamonds that come from depths of over 600 kilometres! These continue to fascinate geologists.
Diamonds also reach the earth's surface through rapidly rising kimberlite magma. Whilst kimberlite is not the parent rock of the diamond, it transports it upwards. Many of these gemstones are very old - some from the Ekati mine in Canada have been estimated to be around 3.5 billion years old, as have those from Siberia and Zimbabwe.
Today's diamond mining
Diamonds are found either in primary deposits (in kimberlite rock) or in secondary deposits. The latter are formed by erosion of the parent rock, which allows the diamonds to accumulate in river beds or elsewhere.
In recent decades, synthetic diamonds have gained in importance and are increasingly being used in jewellery. Nevertheless, it is important to clearly differentiate between synthetic and natural variants, as only natural diamonds may bear the term ‘diamond’ on their own. Treatments to improve appearance or colour must also be disclosed.
Diamonds as an investment
During times of economic uncertainty and inflation, diamonds offer a stable investment. They are a sensible addition to traditional investments such as gold and not only offer aesthetics and rarity, but are also an excellent way to protect and increase wealth.
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