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
Geologists have discovered what they refer to as young diamonds, after analyzing a number of rough diamonds.
It now appears the creation of rough diamonds, may have occurred later in the Earth’s history than was previously thought. Diamond requires extreme temperatures and pressures to form. Geologists though these conditions only existed in the early formation of Earth.
Small impurities in the diamonds could indicate the conditions in which they are formed. So 26 diamonds donated by the De Beers Group where analyzed by a research team in Amsterdam.
Sm-Nd isotope techniques are used by researchers to analyzed the sampled garnet inclusions, Which are a common mineral found in Earth’s mantle and sometimes within the diamonds.
The scientists discovered two sets of diamonds, one of Archaean age 2.95 billion years old thought to be the original source of the diamonds. And then surprisingly the other of Proterozoic age 1.15 billion years old.
A yellow diamond is a coloured diamond characterised by its natural yellow body colour. Yellow must be the predominant colour in the diamond, though it can be modified by other hues, such as green, orange, or brown, which can influence the overall appearance of the stone.
Key Characteristics of Yellow Diamonds
Colour Origin:
The yellow colour in diamonds is primarily caused by the presence of nitrogen atoms within the diamond’s crystal structure. These nitrogen atoms absorb blue light, which results in a yellowish hue. The more nitrogen present, the more intense the yellow colour can become.
This unique characteristic makes yellow diamonds distinct from other coloured diamonds, such as blue diamonds, which gain their colour from the presence of boron.
Colour Variations:
While yellow diamonds are often uniformly yellow, the shade and intensity of the yellow can vary widely. Some may show a subtle, faint yellow, while others exhibit a vibrant, rich yellow that is striking and eye-catching.
The yellow can sometimes be modified by secondary hues. For instance, greenish-yellow diamonds might show a yellow-green tinge, while brownish-yellow diamonds can appear more earthy or muted. These variations in colour can affect the diamond’s overall value and appeal.
Canary Diamonds:
The term “canary diamond” refers to a particularly vivid, intense yellow diamond. These diamonds are much rarer than the more common yellow diamonds, and their colour can range from brilliant lemon yellow to golden hues.
Canary diamonds are highly prized in the market for their bright, vibrant appearance and often fetch higher prices due to their rarity and striking colour.
Rarity and Availability:
Natural yellow diamonds are relatively common compared to some other coloured diamonds, like pink or blue diamonds. However, the intensity and depth of the yellow colour can influence the rarity and desirability of a diamond.
Yellow diamonds are found in several regions around the world, including Africa, Australia, and South America.
Grading Yellow Diamonds:
Like all diamonds, yellow diamonds are graded on a combination of colour, clarity, cut, and carat weight. However, when grading coloured diamonds, the hue, tone, and saturation are the primary focus.
Hue refers to the primary colour of the diamond (in this case, yellow), tone refers to the lightness or darkness of the colour, and saturation measures the intensity of the colour. A high saturation, deep yellow diamond will generally be more valuable than a pale or less saturated one.
The most sought-after yellow diamonds have a vivid yellow hue with high saturation and a pleasing, even colour distribution throughout the stone.
Symbolism and Use:
Yellow diamonds are often associated with happiness, wealth, and success due to their vibrant, sunny appearance. They can also symbolise optimism and joy, making them a popular choice for engagement rings, jewellery, and special gifts.
Due to their striking appearance, yellow diamonds are often used in high-end jewellery, where their bold colour can stand out and create a dramatic effect.
Price and Market Appeal:
The price of yellow diamonds can vary significantly depending on factors like colour intensity, clarity, and size. Vivid yellow diamonds, particularly those with a deep, rich hue, tend to fetch higher prices due to their rarity and the high demand in the luxury market.
However, the relative abundance of yellow diamonds compared to other coloured diamonds like pink or blue means they are often more affordable than rarer varieties.
Yellow diamonds are a beautiful and unique variety of coloured diamonds, with their colour arising from the presence of nitrogen in their crystal structure. While yellow diamonds are relatively common, those with intense yellow hues, such as canary diamonds, are rarer and more valuable. These diamonds are graded based on their hue, tone, and saturation, and are prized for their vivid and radiant appearance. They are a popular choice in fine jewellery, symbolising happiness, wealth, and success, while also offering an affordable yet striking alternative to more expensive coloured diamonds.
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.
The lower-girdle facets are crucial elements in the overall symmetry and brilliance of a diamond. These triangle-shaped facets are located on the pavilion of the diamond, directly adjacent to the girdle, which is the outer edge of the diamond. The pavilion refers to the bottom part of the diamond, below the girdle, which is responsible for reflecting light back through the crown and into the observer’s eye.
Position and Structure
Location: The lower-girdle facets are positioned on the pavilion of the diamond, near the girdle. They are situated just below the main facets of the pavilion, including the main pavilion facets, which are the large, flat surfaces that reflect light into the crown.
Shape: These facets are typically triangle-shaped, although their size and exact proportions can vary depending on the cut of the diamond. In some diamonds, these lower-girdle facets may be slightly elongated or modified, but they usually maintain a triangular form.
Function: The primary function of the lower-girdle facets is to help direct light in the diamond, contributing to its brilliance and scintillation. These facets work by reflecting light that enters the pavilion from below, which then bounces back through the crown of the diamond, creating the visual effects that make diamonds sparkle. The interaction between the light and these facets is essential in maximizing the diamond’s overall visual appeal.
Impact on Diamond Performance
Brilliance:
The brilliance of a diamond is its ability to reflect white light. The lower-girdle facets play an important role in this by directing light from the pavilion back into the crown. When the light is properly reflected, it bounces back to the viewer’s eye, enhancing the diamond’s brightness.
Scintillation:
Scintillation refers to the flashes of light that occur when a diamond moves or is viewed from different angles. The lower-girdle facets help enhance scintillation by creating additional reflections and refractions of light. Their triangular shape and position allow them to catch light from various angles, contributing to the diamond’s overall sparkle.
Symmetry:
Properly aligned and symmetrical lower-girdle facets are essential to the overall symmetry of the diamond. When the facets are evenly proportioned, the diamond will have a more visually appealing appearance, with well-defined light reflections and a balanced sparkle. Any irregularities in the alignment or shape of these facets can lead to an uneven distribution of light, reducing the diamond’s brilliance.
Grading the Lower-Girdle Facets
In diamond grading, the quality of the lower-girdle facets is considered as part of the overall cut grade, which evaluates how well the diamond has been shaped and proportioned to maximize its brilliance, fire, and scintillation. Some of the factors that affect the grading of the lower-girdle facets include:
Size and Proportion:
The size and proportion of the lower-girdle facets should be well balanced with the other facets of the diamond, including the main pavilion facets and the upper girdle facets. Proper proportions contribute to the diamond’s overall symmetry and visual appeal.
Symmetry:
Symmetry is one of the key components of diamond grading. Lower-girdle facets should be symmetrical, with uniform size and placement. Any misalignment or uneven facet sizes can disrupt the flow of light through the diamond and impact its overall performance.
Polish:
A well-polished surface on the lower-girdle facets enhances the diamond’s ability to reflect light. Poor polishing can lead to a dull appearance and reduce the brilliance of the diamond.
Role in Different Diamond Cuts
While lower-girdle facets are typically found in round brilliant cut diamonds, their placement and function can also be seen in other shapes that share similar cutting structures. However, the round brilliant cut diamond relies most heavily on the lower-girdle facets to achieve optimal light performance.
Round Brilliant Cut:
In the round brilliant cut, the lower-girdle facets are particularly important in creating the characteristic sparkle and fire that this cut is known for. The precise arrangement of these facets ensures that the diamond exhibits maximum brilliance and scintillation.
Other Fancy Cuts:
While fancy shapes like emerald, princess, or asscher cuts have different facet structures, they still rely on the principles of light reflection and refraction that are found in the lower-girdle facets of the round brilliant cut. For these shapes, the positioning and number of lower-girdle facets can vary, but their purpose remains the same: to enhance the diamond’s brilliance.
Impact of the Lower-Girdle Facets on Diamond Value
Diamonds with well-proportioned and well-cut lower-girdle facets typically have better light performance, meaning they will display more brilliance, scintillation, and fire. As such, diamonds with ideal or well-graded lower-girdle facets are generally considered more valuable because they are more visually appealing. Poorly proportioned or poorly cut lower-girdle facets can negatively affect the diamond’s performance, reducing its overall desirability and value.
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