The Diamond Certification Laboratory of Australia (DCLA)

The radiant cut is a diamond shape that combines the sparkle of a brilliant cut with the elegance of a square or rectangular shape. It is characterised by its distinct design, where the corners are cut off, creating a rounded appearance. This cut is crafted to maximise the brilliance (sparkle) and fire (colour dispersion) of the diamond, offering a unique and stylish look that is both modern and classic.

Key Features of the Radiant Cut
Shape:

The radiant cut can be either square or rectangular, but it features cut-off corners that distinguish it from other square or rectangular diamond cuts, such as the princess cut.
The shape provides a soft, rounded appearance while maintaining the bold geometric lines of a square or rectangle.
Facet Pattern:

Like the brilliant cut, the radiant cut typically features 58 facets. This facet arrangement helps the diamond reflect light efficiently, maximising its sparkle and brilliance.
Crisscrossing facets are arranged in a manner that enhances the diamond’s light return, creating a lively and vibrant look.
Cornered but Soft:

The cut corners of the radiant cut diamond reduce the sharpness seen in cuts like the princess cut. This helps prevent damage to the corners and makes the diamond more durable. The rounded edges give the diamond a softer look while still maintaining a square or rectangular silhouette.
Brilliance and Fire:

The radiant cut was specifically designed to maximise brilliance and fire, ensuring the diamond reflects light from all angles. This makes it particularly attractive for those seeking a diamond with high sparkle but a slightly different shape from the round brilliant cut.
Proportions and Symmetry in the Radiant Cut
Ideal Proportions: The ideal proportions for a radiant cut diamond depend on its shape. For a square radiant cut, an ideal length-to-width ratio is approximately 1:1, while for a rectangular radiant cut, the ideal ratio tends to fall between 1.25:1 and 1.5:1.
Symmetry: Like other cuts, symmetry plays an essential role in the beauty of a radiant cut diamond. Well-symmetrically cut radiant diamonds reflect light uniformly, creating a vibrant, well-balanced sparkle.
Advantages of the Radiant Cut
High Brilliance – Radiant cuts are designed for maximum sparkle, with 58 facets that reflect light from every angle, creating a lively and dazzling effect.

Versatile Appearance – The radiant cut combines the elegance of the princess cut and the round brilliant cut, making it a versatile choice for various jewellery styles, from engagement rings to earrings and necklaces.

Durability – The cut-off corners reduce the risk of chipping compared to the sharp corners of a princess cut, making radiant cuts a more practical option for everyday wear.

Unique Shape – The radiant cut offers a distinctive look that stands out from other popular cuts like round or princess cuts. Its ability to combine the best of both shapes makes it a preferred choice for those seeking something different.

Value for Money – The radiant cut typically retains more of the rough diamond compared to round brilliant diamonds, making it a cost-effective option for larger stones.

Setting Options for Radiant Cut Diamonds
Prong Setting:

A four-prong or eight-prong setting is commonly used to secure radiant cut diamonds, allowing maximum light exposure and highlighting the stone’s brilliance.
The prongs can be placed along the corners of the diamond to emphasise its shape.
Bezel Setting:

A bezel setting can encircle the edges of the diamond with metal, offering extra protection to the corners while providing a sleek, modern look.
Halo Setting:

A halo setting, where smaller diamonds encircle the centre radiant cut diamond, is a popular choice. It enhances the diamond’s size and sparkle while adding extra brilliance.
Tension Setting:

The tension setting is a bold, modern way to showcase a radiant cut diamond. The diamond appears to be floating between two metal bands, offering a minimalist yet striking design.
Radiant Cut vs. Other Cuts
Cut Type Shape Brilliance Best Feature
Radiant Cut Square/Rectangular Very High Unique blend of square/round elegance
Princess Cut Square Very High Sharp edges, square shape
Emerald Cut Rectangular Moderate Elegant, step-cut style
Round Brilliant Circular Very High Maximum brilliance and fire
Cushion Cut Square/Rounded Corners High Soft, vintage appearance

The radiant cut is a stunning and versatile diamond shape that balances brilliance and fire with the elegance of a square or rectangular shape. Its unique cut corners not only enhance its visual appeal but also improve the diamond’s durability. With high brilliance, a striking shape, and the ability to suit a variety of settings, the radiant cut is an excellent choice for those seeking a beautiful yet distinctive diamond that stands out in any piece of jewellery.

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.

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.

The Round Brilliant Cut is by far the most popular and widely recognised diamond cut, known for its ability to showcase a diamond’s brilliance, fire, and scintillation. It is designed to maximise the diamond’s reflective qualities and ensure that the stone sparkles to its fullest potential. The cut is characterised by its circular outline and cone-shaped pavilion, with a set number of facets that are precisely arranged to enhance the light performance of the diamond.

Key Features of the Round Brilliant Cut
Shape and Outline:

As the name suggests, the round brilliant cut is defined by its circular shape, which makes it instantly recognisable. This symmetrical shape enhances the light return, which is one of the key factors that contributes to the diamond’s brilliance. The round shape also provides a classic aesthetic, making it a timeless choice for engagement rings and other fine jewellery.
Facets:

The standard round brilliant cut typically has 57 facets, though some stones may have 58 facets if the culet (the small flat facet at the bottom of the diamond) is also included. These facets are carefully cut to reflect and refract light, creating the characteristic sparkle and fire that makes the round brilliant cut so desirable.
The facets of a round brilliant diamond are divided into three main sections: the crown, girdle, and pavilion:
Crown: The upper portion of the diamond, which includes the table (the flat top surface) and the facets that radiate from it.
Pavilion: The lower portion, which is cone-shaped and holds the majority of the diamond’s facets.
Girdle: The thin band around the diamond that separates the crown from the pavilion.
Brilliance, Fire, and Scintillation:

The brilliance of a round brilliant cut diamond refers to its white light reflection, or how much light the diamond returns to the eye. The angles and arrangement of the facets are designed to allow light to enter through the table, reflect off the internal surfaces, and return through the top of the diamond, creating that dazzling sparkle.
Fire refers to the flashes of coloured light that appear as the diamond moves. The number of facets in a round brilliant cut maximises the dispersion of light, creating vibrant flashes of red, blue, and yellow as the stone is rotated.
Scintillation is the term for the sparkle or twinkle of the diamond as it moves. A round brilliant cut diamond will exhibit high scintillation, meaning that it produces continuous flashes of light with every slight motion.
Cut Quality:

The cut quality of a round brilliant diamond is one of the most important factors influencing its overall beauty. The proportions of the diamond, including the table size, crown angle, pavilion depth, and girdle thickness, all play a crucial role in how well the diamond performs with light.
A well-cut diamond will have a perfect balance between brilliance, fire, and scintillation, with all the facets working together to maximise the diamond’s light return.
Diamonds with poor proportions will leak light, reducing the brilliance and fire of the stone, and making the diamond appear duller.
Round Brilliant Cut vs Other Cuts
The round brilliant cut is the most commonly chosen diamond shape, largely because it offers the best overall light performance. However, there are other shapes and cuts, each with their own appeal:

Cut Shape Facets Light Performance Appeal
Round Brilliant Circular 57 or 58 Exceptional brilliance, fire, scintillation Timeless, classic, maximum sparkle, highly popular
Princess Cut Square or Rectangular 57 Excellent brilliance, good scintillation Modern, sharp, distinctive, highly popular
Emerald Cut Rectangular 58 Moderate brilliance, strong clarity and transparency Elegant, sophisticated, highlights clarity
Cushion Cut Square with rounded corners 58 Good brilliance, antique-like appeal Romantic, vintage-inspired, soft sparkle
Oval Cut Oval 58 Similar to round, slightly elongated brilliance Unique, elegant, elongates the finger
Asscher Cut Square 58 Exceptional clarity, vintage look Art Deco style, striking clarity, bold aesthetic
Marquise Cut Boat-shaped 58 High brilliance, elongates appearance Dramatic, elegant, optimises carat weight
Advantages of the Round Brilliant Cut
Maximum Brilliance:

The round brilliant cut is specifically designed to maximise the brilliance of a diamond. The precise facet arrangement and angles ensure that the diamond performs optimally in terms of light reflection and refraction, resulting in a highly sparkling stone.
Timeless and Classic:

The round brilliant cut is a timeless design, and its classic appeal makes it one of the most popular choices for engagement rings and other fine jewellery. Its symmetrical shape is universally appealing, and it remains a symbol of elegance and refinement.
Versatility:

A round brilliant cut diamond can complement a wide variety of settings, from solitaire rings to halo settings or more intricate designs. The shape’s versatility means it suits both traditional and modern jewellery styles, making it a versatile choice for all types of jewellery.
Resale Value:

Round brilliant cut diamonds tend to hold their value well in the market. Due to their popularity and high demand, they are often considered a good investment choice, with strong resale value.
Considerations When Choosing a Round Brilliant Cut
Cut Quality:

The cut of a round brilliant diamond is one of the most important factors in determining its overall appearance. It’s essential to consider the diamond’s proportions, as a well-cut stone will showcase the best light performance. Always ensure that the diamond has been graded by a reputable lab, such as the GIA or DCLA, to ensure the cut is of high quality.
Budget:

Round brilliant cut diamonds are often priced at a premium due to their popularity and demand. While they offer exceptional beauty, it’s important to set a budget that aligns with your preferences and financial considerations. Smaller diamonds or diamonds with lower colour or clarity grades may be more affordable, while larger, higher-quality stones will command a higher price.
Carat Size:

The size of the round brilliant cut diamond also impacts its value. Larger stones typically cost more, and their brilliance is even more pronounced due to the increased surface area. However, even smaller round brilliant diamonds can deliver incredible sparkle and beauty when cut well.

The round brilliant cut remains the most popular and sought-after diamond shape due to its exceptional brilliance, sparkle, and timeless appeal. Its carefully planned facet arrangement ensures optimal light performance, creating a diamond that dazzles with every movement. Whether as an engagement ring, a pendant, or earrings, the round brilliant cut continues to captivate and delight, making it the perfect choice for anyone seeking a diamond with unmatched brilliance and elegance.