The Diamond Certification Laboratory of Australia (DCLA)
Buy and sell diamonds with the help of the experts
Sotheby’s Auctioneers announced the upcoming auction of the Raj Pink diamond.
Weighing 37.30 carats the Pink diamond is the largest Fancy Intense Pink Diamond, according to Sotheby’s.
The Pink Diamond will feature at the auction house’s Magnificent Jewels in Geneva next month, and is estimated to fetch $20 million to $30 million USD.
The Original Rough Diamond was studied for over a year before the master cutter finished the polished Raj Pink Modified Cushion Brilliant cut
Exceptional Large Pink Diamond Discovered in Russia Could Be Most Expensive ever by Alrosa
Alrosa Diamond Mining is examining the rough and will decide on whether to sell it as a rough diamond, or cut and polish it in house.
The Rough Diamond is high quality and could make it Alrosa’s most expensive diamond if it decides to cut and polished the stone.
Chief Executive Officer Sergey Ivanov said Alrosa has mainly focused on rough diamond mining, will increase revenues from its polishing unit.
A rough diamond is a diamond in its natural state, exactly as it is found deep within the Earth. It has not yet undergone any form of cutting, polishing, or alteration. Rough diamonds are typically irregular in shape, with a variety of textures, colours, and surface conditions, ranging from clear and transparent to opaque and coloured.
These diamonds are generally discovered in kimberlite pipes (volcanic formations) or alluvial deposits (water-worn areas), and they are extracted through a process of mining. Once found, rough diamonds are carefully sorted and graded based on their size, shape, colour, and clarity before they are sent to gem cutters for transformation into polished stones.
Key Characteristics of Rough Diamonds
Shape:
Rough diamonds are typically irregular, with shapes that can range from octahedral (two pyramidal shapes joined together) to dodecahedral (a 12-sided form). These shapes are determined by the crystal structure of the diamond and can vary widely.
The rough shape is not intended for jewellery, and the gem cutters will plan how to cut the stone based on its natural geometry to maximise yield and minimise waste.
Colour:
Rough diamonds can appear in a wide range of colours, from colourless and transparent to shades of yellow, brown, or even rare colours such as blue, green, or pink.
The final colour of the diamond will depend on its internal structure and any trace elements present in the rough material. Some rough diamonds are even tinted due to the presence of minerals or impurities.
Clarity:
In their natural form, rough diamonds may have a variety of inclusions and blemishes, such as tiny air bubbles or mineral inclusions trapped within the crystal. These internal flaws are often visible to the naked eye or under magnification, though they can be reduced or eliminated during the cutting and polishing processes.
Size:
Rough diamonds vary greatly in size, from small pebbles to large stones weighing several carats. Larger rough diamonds are often considered more valuable, especially if they possess good colour and clarity, as they can be cut into high-quality finished diamonds.
The Journey of a Rough Diamond
Extraction:
Rough diamonds are mined from the Earth, typically through open-pit mining, underground mining, or alluvial mining (searching for diamonds in riverbeds or coastal regions). Mining companies extract the rough stones from kimberlite pipes or riverbeds, often using advanced technology to locate diamond deposits deep underground.
Sorting and Grading:
Once extracted, rough diamonds are sorted based on their size, colour, clarity, and shape. Each diamond is examined to determine its potential for cutting and polishing. Some rough diamonds are too flawed or small to be cut into gem-quality stones and may be used for industrial purposes instead.
The DCLA (Diamond Certification Laboratory of Australia) offers rough diamond services to help classify and grade rough diamonds. They use their expertise to evaluate the quality of rough diamonds and assist in planning the best course of action for cutting and polishing.
Cutting and Polishing:
After sorting, the rough diamond is sent to skilled gem cutters, who use advanced techniques and tools to transform the stone into its finished form. The cutting process involves careful planning to maximise the yield (the amount of diamond produced from the rough stone) while aiming to enhance the diamond’s brilliance, fire, and overall appearance.
The diamond may be cut into a variety of shapes, such as round, emerald, princess, or cushion, depending on the rough stone’s shape and quality.
Grading:
Once the diamond is cut and polished, it is then graded according to the 4 Cs – Carat, Colour, Clarity, and Cut. This grade determines the diamond’s final value, and certificates from recognised laboratories such as DCLA are used to authenticate the quality of the diamond.
Uses of Rough Diamonds
Gem-quality Diamonds:
The primary use of rough diamonds is for gemstone production, where they are cut and polished into diamonds for use in engagement rings, earrings, necklaces, and other high-end jewellery.
Industrial Diamonds:
Some rough diamonds, particularly those with significant imperfections, are not suitable for use in jewellery. These diamonds are used for industrial purposes, where their hardness is highly valued. Industrial diamonds are employed in applications such as cutting, grinding, drilling, and polishing, where the diamond’s extreme hardness makes it ideal for cutting or shaping other materials.
The rough diamond is the very first step in the life cycle of a diamond. Found in the earth in its natural form, it is then extracted, sorted, and carefully crafted into the sparkling gemstones that are valued in fine jewellery. Due to their rarity and the complexity of their transformation, rough diamonds represent both the mystery of nature and the skill of the craftsmen who shape them into stunning finished products.
A red diamond is an extremely rare and captivating coloured diamond with a natural red body colour. This distinctive hue is often considered the most rare of all diamond colours, with its unique shade being the result of an irregular crystal structure. Unlike other coloured diamonds, the red colour in red diamonds is not caused by the presence of impurities, but by specific structural defects within the crystal lattice, which affects how the diamond interacts with light.
Key Characteristics of Red Diamonds
Colour:
The red in red diamonds must be the predominant colour, and it may be modified by subtle undertones of pink or purple. These undertones add depth and complexity to the diamond’s overall appearance, creating a dynamic play of colour under different lighting conditions.
Red diamonds can range in tone from a light pinky-red to a deep, intense red, with the most prized examples exhibiting a vivid and saturated hue. The richness and intensity of the red are key factors in determining a red diamond’s rarity and value.
Colour Origin:
The distinct red colour of these diamonds is not due to traditional colouring agents like nitrogen or boron, which are often responsible for the hues of other coloured diamonds. Instead, the red colour arises from structural anomalies in the crystal lattice. These distortions cause light to bend in unique ways, giving the diamond its characteristic deep red shade.
The exact mechanism behind the creation of red diamonds is not entirely understood, which adds to their mystery and allure.
Rarity:
Natural red diamonds are the rarest of all coloured diamonds. They are so rare that they account for less than 0.1% of all natural diamonds. Their scarcity is due to the highly specific conditions required to form these diamonds. The majority of red diamonds come from a few select mines, particularly the Argyle Mine in Australia, which is one of the only sources of natural red diamonds.
As a result of their extreme rarity, red diamonds are often considered investment-grade stones, with prices escalating due to limited supply and growing demand.
Colour Grading:
The grading of red diamonds is somewhat different from other coloured diamonds. Red diamonds are typically graded on their colour saturation and intensity. Diamonds with a higher degree of vivid red colour and strong saturation are classified as fancy red diamonds, which are among the most valuable and sought-after types of coloured diamonds.
The Fancy Red classification is a coveted category, where the diamond displays a full, intense red hue with minimal interference from other colours.
Value and Investment
Investment Potential:
Due to their extreme rarity, high demand, and unique beauty, red diamonds are considered a valuable investment. As the supply of natural red diamonds continues to dwindle, especially with the closure of the Argyle Mine, prices are expected to rise steadily over time.
Red diamonds have become highly sought-after in the auction world, where they consistently fetch premium prices.
Pricing Factors:
The price of red diamonds is primarily determined by their colour quality, with the intensity and saturation of the red being the most important factors in determining value. Additionally, the size of the diamond also plays a role in its price, with larger red diamonds being exceptionally rare and significantly more expensive.
Red Diamond vs Other Coloured Diamonds
Diamond Colour Rarity Colour Tone Key Features
Red Extremely Rare Vivid Red, Deep Red Most rare, unique structural colour origin
Pink Rare Soft Pink to Vivid Pink Lighter hue, sometimes found with red undertones
Blue Rare Deep Blue to Light Blue Caused by boron, highly prized for its striking colour
Green Rare Light Green to Intense Green Natural radiation exposure causes the green hue
Yellow Common Light Yellow to Intense Yellow Caused by nitrogen, often brighter than other colours
Black Fairly Rare Deep, opaque black Intense colour, may have inclusions contributing to hue
Red Diamonds in Jewellery
Engagement Rings:
Red diamonds make a bold and captivating choice for engagement rings. Their rare and striking colour is perfect for individuals seeking something extraordinary and one-of-a-kind. When set in platinum or white gold, the red hue is often accentuated, creating a stunning contrast that is both elegant and memorable.
High-End Jewellery:
Due to their rarity and prestige, red diamonds are often featured in luxury jewellery collections and can be seen in high-end pieces, including necklaces, bracelets, earrings, and brooches. Their striking appearance and scarcity make them a statement piece in any collection.
Fancy Settings:
Red diamonds are typically set in settings that showcase their vivid colour, such as halo settings (where smaller diamonds surround the central red diamond) or three-stone designs that highlight the rarity and beauty of the diamond.
The red diamond is one of the rarest and most beautiful gemstones in the world, prized for its deep, captivating red hue and its unique structural formation. With limited availability and high demand, red diamonds are not only a luxurious addition to any jewellery collection but also an investment asset. Whether used in engagement rings, necklaces, or other fine jewellery, red diamonds are a symbol of both rarity and elegance, making them one of the most sought-after coloured diamonds in the world.
In the diamond industry, a point is a unit of weight used to measure diamonds and other gemstones. One point is equal to one hundredth (1/100) of a carat, or 0.01 carats.
Understanding Points in Diamond Weight
Diamonds are weighed in carats (ct), with each carat divided into 100 points. This system allows for precise measurements, especially for smaller diamonds.
For example:
A 15-point diamond weighs 0.15 carats and is sometimes referred to as a “fifteen-pointer.”
A 50-point diamond weighs 0.50 carats, also called a “half-carat” diamond.
A 100-point diamond equals 1.00 carat, making it a one-carat diamond.
Why Points Matter
Precision – Points allow for highly accurate diamond weight measurement, especially for small diamonds where even minor differences in weight can affect value.
Pricing – Since diamond prices are calculated per carat, even a small difference in weight (e.g., 0.49 ct vs. 0.50 ct) can significantly impact the price.
Common Usage – Jewelers and gemologists frequently use the term “points” when referring to diamonds under one carat, as it simplifies communication of weight.
Example Diamond Sizes in Points
Points Carats Common Name
10 pts 0.10 ct Ten-pointer
25 pts 0.25 ct Quarter-carat
50 pts 0.50 ct Half-carat
75 pts 0.75 ct Three-quarter carat
100 pts 1.00 ct One-carat
While points are commonly used for diamonds below 1.00 carat, larger diamonds are generally described in carats rather than points (e.g., a 1.25-carat diamond rather than a 125-pointer).
The point system is an essential part of diamond grading and pricing, providing precise measurements that ensure accuracy in weight calculation. Whether buying or selling a diamond, understanding points can help in making informed decisions about size, value, and pricing.
Pinpoints are extremely small diamond crystal inclusions that are typically too tiny to distinguish their individual shapes, even under magnification. When viewed under 10x magnification, a single pinpoint appears as a minute, white or black “dot” within the diamond. While a single pinpoint is often insignificant and may not affect a diamond’s overall clarity or brilliance, multiple pinpoints grouped together can form a cloud—a hazy or milky area within the diamond that can impact its transparency and light performance.
These inclusions are a natural part of a diamond’s formation process and are commonly found in many diamonds. Depending on their number, size, and location, pinpoints can have varying effects on a diamond’s clarity grade. In some cases, when they are sparsely distributed, they have little to no visible impact. However, if they are densely clustered, forming a significant cloud, they may lower the diamond’s clarity rating and slightly reduce its brilliance by affecting how light passes through the stone.
Pinpoints are one of the many inclusions that gemologists assess when grading diamonds, and they are often documented on a diamond’s grading report issued by reputable gemological laboratories such as the GIA (Gemological Institute of America) or DCLA (Diamond Certification Laboratory of Australia).
A pit is a type of diamond blemish that appears as a tiny surface indentation or opening on the diamond’s exterior. These minute imperfections can be caused by natural formation processes, the cutting and polishing process, or general wear and tear over time. Pits are typically small and may require 10x magnification to be seen clearly, though larger pits can sometimes be visible to the naked eye.
When pits are larger and deeper, they are classified as cavities, which can have a more noticeable impact on a diamond’s clarity and durability. Pits and cavities are usually found on the table or facet junctions of a diamond, where they may affect the overall finish of the stone.
Pits can influence a diamond’s polish grade, as they interrupt the smoothness of the surface. While minor pits may not significantly impact a diamond’s appearance or value, excessive or deep pits can detract from its brilliance and make the stone more vulnerable to dirt accumulation or further damage.
In professional diamond grading reports from laboratories like the GIA or DCLA, pits are noted as part of the stone’s clarity characteristics. Jewelers and diamond cutters may attempt to minimize the visibility of pits through careful polishing, though in some cases, deep pits or cavities may require minor re-cutting to improve the diamond’s overall finish.
A coloured diamond with a natural pink body colour. Pink must be the predominant colour, but it may be modified by shades of purple, orange, and yellow. The colour in natural pink diamonds is created by irregular crystal structure. Some pink coloured diamonds with sufficient saturation fall into the valuable fancy pink colour category of diamonds.
A pink diamond is a rare and highly sought-after coloured diamond that exhibits a natural pink body colour. To be classified as a pink diamond, pink must be the predominant hue, though it may be modified by secondary tones such as purple, orange, or yellow.
Unlike most coloured diamonds, which owe their hues to chemical impurities, the captivating colour of natural pink diamonds is attributed to distortions in their crystal lattice structure. These distortions, formed under immense pressure during the diamond’s geological formation, alter the way light interacts with the stone, producing its signature pink hue.
Pink diamonds vary in intensity, ranging from delicate pastel shades to deep, vivid pinks. Those with higher colour saturation are classified as Fancy Pink diamonds, a designation that significantly enhances their value. The most desirable pink diamonds display pure, strong pink tones with minimal secondary colours.
These exquisite gems are among the rarest diamonds in the world, with the finest specimens historically sourced from the Argyle mine in Australia, which ceased operations in 2020. The mine’s closure has further increased the rarity and value of high-quality pink diamonds. Today, they remain a prized choice for collectors and investors, often fetching record-breaking prices at auctions.
Kimberlite is an igneous rock, typically blue or green in colour, from which most diamonds are mined. It is of particular interest in the study of diamonds because it serves as the primary host rock for the formation and occurrence of these precious stones. Kimberlite is found in specific geological structures known as kimberlite pipes, which are deep, vertical fissures or conduits in the Earth’s crust. These pipes were formed by volcanic activity, and they are the main source of natural diamonds that are mined today.
Formation and Composition of Kimberlite
Kimberlite is an ultramafic rock, meaning it contains a high proportion of magnesium and iron, with low silica content. The primary components of kimberlite include:
Olivine: A green mineral that is a common constituent of kimberlite, contributing to its characteristic colour.
Pyroxenes: A group of minerals that also form part of kimberlite’s composition.
Carbonates: Minerals such as calcite and dolomite can be found in kimberlite, sometimes in large quantities.
Clay Minerals and Volcanic Ash: In some cases, kimberlite also contains elements derived from the surface, such as clay minerals or volcanic debris.
Diamond Crystals: Most notably, kimberlite contains diamonds, though the quantity and size of these diamonds vary.
The volcanic activity responsible for the formation of kimberlite pipes involves the eruption of magma from deep within the Earth’s mantle. This magma, under extremely high pressure and temperature, ascends through the Earth’s crust, bringing with it diamonds that formed under similar high-pressure conditions. Kimberlite, upon solidification, traps these diamonds within the rock, where they remain until mining operations bring them to the surface.
Kimberlite Pipes: The Primary Source of Diamonds
The most famous source of diamonds, kimberlite pipes, are vertical geological formations that originate from deep beneath the Earth’s surface. These pipes are often cylindrical in shape, and their formation is associated with ancient volcanic eruptions. As the magma ascends through the Earth’s crust, it forms a narrow, funnel-like conduit. Over millions of years, erosion and weathering can expose kimberlite pipes, allowing diamond mining to occur.
These pipes are typically surrounded by much older and harder rocks, often making it difficult to access the diamonds. The kimberlite itself can also contain other valuable minerals such as garnet, ilmenite, and chromite, but it is the diamonds embedded within the kimberlite that are the primary target of mining efforts.
The Role of Kimberlite in Diamond Mining
Kimberlite plays a crucial role in the discovery and extraction of diamonds. Mining operations often target kimberlite pipes, as they are the most reliable source of diamonds in nature. The process of mining kimberlite involves:
Exploration: Geologists and prospectors search for kimberlite pipes using various techniques such as aerial surveys, satellite imagery, and ground sampling. The distinctive blue or green colour of the rock can also be used as an indicator of its presence.
Extraction: Once a kimberlite pipe is located, it is typically extracted through either open-pit or underground mining techniques. Open-pit mining involves removing large quantities of surface material to reach the kimberlite layer, while underground mining involves digging shafts to reach deeper deposits.
Processing: After kimberlite is extracted, it is crushed and sorted to separate the diamonds from the surrounding rock and other minerals. This is typically done through a combination of mechanical crushing, gravity separation, and sometimes, advanced techniques such as X-ray sorting or dense media separation.
Geological and Geographic Distribution of Kimberlite
Kimberlite is found in specific geographic regions, primarily in ancient cratons—stable areas of the Earth’s crust that have remained relatively undisturbed for billions of years. These regions include:
Africa: The continent is home to several large kimberlite pipes, including the famous Kimberley Mine in South Africa, which has been historically significant for diamond mining.
Russia: Russia contains several diamond-producing kimberlite pipes, particularly in Siberia, with the Yakutia region being a major source of diamonds.
Canada: The discovery of kimberlite pipes in Canada’s Northwest Territories led to the establishment of large-scale diamond mining operations, such as the Ekati and Diavik mines.
Australia: The Argyle Mine in Western Australia, which produces significant quantities of pink and red diamonds, is also a notable source of kimberlite.
While kimberlite pipes are present on all continents, the largest and most significant diamond-producing regions are found in Africa, Russia, and Canada.
Importance and Rarity of Kimberlite Pipes
While kimberlite pipes are the main source of natural diamonds, they are relatively rare. The conditions required for kimberlite formation are very specific, and only a small number of these pipes have been discovered and mined for diamonds. Geologically speaking, kimberlite pipes are often formed in ancient and stable parts of the Earth’s crust, where volcanic activity can reach the depths necessary for diamond formation.
The rarity and difficulty of accessing kimberlite pipes make diamonds sourced from these pipes valuable commodities. The unique geological conditions under which kimberlite forms, combined with the rarity of pipes, contribute to the high value of diamonds that originate from these sources.
Kimberlite vs. Lamproite: Other Sources of Diamonds
While kimberlite is the most well-known source of diamonds, lamproite is another type of volcanic rock that can also host diamonds. Lamproite is less common than kimberlite, but some significant diamond deposits, such as those at the Argyle Mine in Australia, have been discovered in lamproite pipes. However, kimberlite remains the more prominent and studied source of diamonds worldwide.
Only about 20% of mined diamonds are of gem quality, meaning they meet the necessary standards for use in jewellery. The remaining 80% fall into the industrial-grade category, used in various commercial and technological applications. Let’s explore this in more detail:
Breakdown of Diamond Quality
Gem-Quality Diamonds (≈20%)
These diamonds are characterised by high clarity, colour, and cut quality, making them desirable for jewellery.
They undergo cutting and polishing to enhance their brilliance before being set in rings, necklaces, earrings, and other fine jewellery.
Their value depends on the 4 Cs (Carat, Cut, Colour, Clarity) and whether they are natural or treated.
Industrial-Grade Diamonds (≈80%)
These diamonds are lower in clarity, may have visible inclusions, and often exhibit yellow, brown, or grey colours that make them unsuitable for jewellery.
They are used in industries due to their hardness and durability, which are essential for cutting, drilling, grinding, and polishing applications.
Common uses include:
Diamond-tipped drill bits and saw blades for construction and mining.
Abrasive powders for polishing and grinding metals.
High-tech applications, such as semiconductors and heat conductors in electronics.
Why the Low Percentage of Gem-Quality Diamonds?
Several factors contribute to why only a small fraction of mined diamonds qualify as gem-grade:
Formation Conditions: Natural diamonds form under extreme pressure and temperature deep within the Earth’s mantle. Impurities or irregular growth can affect their clarity, colour, or shape.
Inclusions and Blemishes: Many diamonds contain internal inclusions (tiny fractures or foreign minerals) and external blemishes, making them less suitable for jewellery.
Colour and Transparency: Gem-quality diamonds are typically colourless to light yellow (D-Z on the GIA colour scale). Many mined diamonds have a strong brown or grey tint, reducing their desirability.
Cutting Yield: Some rough diamonds, even if of good quality, may be inefficiently shaped for cutting into marketable gemstones.
Impact on the Diamond Market
Rarity Drives Value: Since high-quality diamonds are less common, they retain their value better than industrial-grade diamonds.
Lab-Grown Diamonds: The gap in supply between industrial and gem-quality diamonds has led to advancements in lab-grown diamonds, which can be produced with high clarity and controlled quality.
Recycling & Recutting: Some lower-quality diamonds can be recut or treated (e.g., laser drilling, fracture filling) to enhance their appearance, but these diamonds are usually less valuable than untreated stones.
The fact that only 1 in 5 mined diamonds meets gem-quality standards highlights the rarity and value of fine diamonds. This also influences pricing, sourcing strategies, and market trends, as both natural and lab-grown diamonds compete in the luxury and industrial sectors.