What is Diamond ?
Diamond is one of the best-known and most sought-after gemstones. Diamond is one gemstone that needs no introduction, the most famous of all the precious stones. Diamonds have been used in jewelry for many generations, and are coveted perhaps more than any other gemstone. The story of Diamond begins over 500 million years ago, deep within the Earth’s Mantle, where they were formed under immense pressure. They have been used as decorative items since ancient times. The hardness of diamond and its high dispersion of light—giving the diamond its characteristic "fire"—make it useful for industrial applications and desirable as jewellery.
The earliest diamonds were found in India in 4th century BC, although the youngest of these deposits were formed 900 million years ago. A majority of these early stones were transported along the network of trade routes that connected India and China, commonly known as the Silk Road. At the time of their discovery, diamonds were valued because of their strength and brilliance, and for their ability to refract light and engrave metal. Diamonds were worn as adornments, used as cutting tools, served as a talisman to ward off evil, and were believed to provide protection in battle. In the Dark Ages, diamonds were also used as a medical aid and were thought to cure illness and heal wounds when ingested.
Surprisingly, diamonds share some common characteristics with coal. Both are composed of the most common substance on earth: carbon. What makes diamonds different from coal is the way the carbon atoms are arranged and how the carbon is formed. Diamonds are created when carbon is subjected to the extremely high pressures and temperatures found at the earth’s lithosphere, which lies approximately 90-240 miles below the earth’s surface.
Until the 18th century, India was thought to be the only source of diamonds. When the Indian diamond mines were depleted, the quest for alternate sources began. Although a small deposit was found in Brazil in 1725, the supply was not enough to meet world demands.
In 1866, 15-year-old Erasmus Jacobs was exploring the banks of the Orange River when he came across what he thought was an ordinary pebble, but turned out to be a 21.25-carat diamond. In 1871, a colossal 83.50-carat deposit was unearthed on a shallow hill called Colesberg Kopje. These findings sparked a rush of thousands of diamond prospectors to the region and led to the opening of the first large-scale mining operation which came to be known as the Kimberly Mine. This newly discovered diamond source increased the world’s diamond supply substantially, resulting in a significant decrease in their value. The elite no longer considered the diamond a rarity, and began to replace this “common” stone with colored gemstones. Emeralds, rubies, and sapphires became more popular choices for engagement ring stones among the upper class.
Properties And Applications
Diamond is the hardest naturally occurring material known. Over 70 percent of diamonds are used for industrial applications and demand for the material is continuously growing.
Natural diamond is carbon crystals that forms under high temperature and pressure conditions that exist only about 100 miles beneath the earth’s surface. It is typically about 99.95 percent carbon. The other 0.05 percent can include one or more trace elements, which are atoms that aren’t part of the diamond’s essential chemistry.
Diamond’s crystal structure is isometric, which means the carbon atoms are bonded in essentially the same way in all directions.
Another mineral, graphite, also contains only carbon, but its formation process and crystal structure are very different. The result is that graphite is so soft that you can write with it, while diamond is so hard that you can only scratch it with another diamond.
Without any one of these factors, diamond might be just another mineral. Fortunately, though, this special combination of chemical composition, crystal structure, and formation process gives diamonds the qualities that make them extraordinary.
Besides the hardness, diamond provides an impressive combination of chemical, physical and mechanical properties :
- Low coefficient of friction
- High thermal conductivity
- High electrical resistivity
- Low thermal expansion coefficient
- High strength
- Broad optical transparency from ultra violet to infra red
- Resistant to chemical corrosion
- Biologically compatible
Example of applications
The use of diamond has grown enormously since World War 2, exploiting the unique combination of properties and the increased availability of the material as synthesis methods developed.
- Wear components
- Cutting tools
- Thermal management (in e.g. substrates, heat spreaders and heat sinks)
- Semiconductor devices
- Optical components
- Other high performance applications
Fancy Colored Diamonds ?
Colored diamonds are known in the jewelry trade as “fancy diamonds”. They are available in an array of colors, tones and saturations – some are certainly more rare than others, but overall colored diamonds are far more rare than their white counterparts.
Diamonds come in almost every color you could imagine, but some hues are seen more often than others. For example, pink and yellow diamonds have a high demand and are mined at a higher rate than green, purple, orange or blue diamonds. Regardless, a colored diamond is a rare and incredible item and their value increases over time.
Colored diamond grading terminology uses a combination of fancy grades and color descriptions to define a diamond’s characteristic color.
Hue is the dominant color of the diamond. It can be affected by the presence of ‘modifiers’ or ‘tints’, which are additional hues within a stone. A diamond can be a single color, such as pink, or it can have a secondary color, for example if a pink diamond had a purple tint, it would be described as a ‘purplish-pink diamond’.
Saturation refers to the strength or intensity of the hue of main color exhibited from the diamond. Saturation of diamonds with a lighter tone can range from ‘light’ to ‘intense’ to ‘vivid’. For darker diamonds, descriptions can range from ‘dark’ to ‘deep’.
Tone refers to how light or dark the diamond appears. This is typically determined by how much brown, black, grey or white is present in the stone.
in the grading report the color aspect is detailed further by describing :
- Origin : Describes whether the stone is a natural or treated color.
- Grade : Hue, tone and saturation are all considered when grading color. you can used the following grades to identify color intensity: faint, very light, light, fancy light, fancy, fancy intense, fancy vivid, fancy dark, fancy deep.
- Distribution : Assesses how evenly spread the color is throughout the diamond. The color will be graded as ‘even’ or ‘uneven’ depending on how consistent the concentration of color appears.
A fancy color diamond of moderate tone will be assigned a grade according to its overall face up appearance. These grades are Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid, Fancy Dark and Fancy Deep.
Colors do not reach high levels of saturation at lighter tones; nor does the eye discern as many colors at these locations in color space. Therefore, fewer color terms are used. The gray band on the illustration at right shows the relative locations of the samples on the chart. These diamonds often correspond grades of Light and Fancy Light.
Colored diamonds with a "Light" grade do not reach high levels of saturation.
Colored diamonds with a "Fancy Light" grade also do not reach high levels of saturation, but they will exhibit a slightly darker tone or stronger saturation than a "Light" grade.
"Fancy Intense" grade colored diamonds have a lighter tone, with a significantly stronger color saturation.
"Fancy Vivid" implies a relatively lighter tone with the strongest possible saturation. For "darker" colors such as blue, Fancy Vivid can only refer to a diamond with a fully saturated darker blue.
"Fancy Dark" diamonds have a darker tone with a relatively strong saturation of color.
A diamond with the darkest tone and with some color saturation is usually graded as "Fancy Deep".
Similarly to light-toned diamonds, dark diamonds do not reach high levels of color saturation.
Certain colors almost never come in saturations that would be called vivid. Blue diamonds for instance commonly have a grey modifier and the best appearance for blue is typically a darker tone. The Hope diamond is a Fancy Deep Greyish Blue.
Many colored diamonds feature a secondary color that is visibly present. If the secondary color is strong enough, added that modifier to the primary hue. If the primary and secondary color are virtually even throughout the diamond, these will be described using the two colors. For example, “Purple Pink. If the primary color is dominant, the secondary color will be described as “ish”, for example, “Purplish Pink”. Confusingly, the secondary color precedes the dominant color in the description, meaning “Purplish Pink” would indicate that the primary color is pink, and the secondary color is purple.
Since color is such an important element in the desirability and market value of a fancy colored diamond, purity and depth of color have a huge impact on the final price.
Analysis of colored diamonds
Pink is a rare natural color in diamonds. It occurs when the diamond is subjected to stress within the Earth, and those forces cause glide planes of carbon atom displacement within the diamond crystal. When light passes through the planes, red light is selectively transmitted. The red light appears pink when the selective transmission is weak. The selective transmission is rarely strong enough to produce a red color.
Yellow is the second most common natural color in diamonds. The color is usually caused by nitrogen atoms substituting for carbon in the diamond crystal lattice. This defect causes diamond to selectively absorb blue light and selectively transmit yellow.
Blue diamonds are rare in nature. The blue color is most often caused by boron atoms substituting for carbon atoms in the crystal lattice of diamonds that have formed at extreme depths. As little as one boron atom per million carbon atoms can produce a noticeable blue color. Boron in the diamond crystal causes the selective absorption of red light and the selective transmission of blue.
Brown is the most common natural color in diamonds. The color develops when plastic deformation creates planes of missing and displaced carbon atoms in the diamond crystal lattice. These are known as glide planes, and they are where the brown color is concentrated. They can appear as a series of parallel color bands in the diamond known as "graining".
Green diamonds are very rare in nature. The color usually develops when high-energy radiation emitted by nearby radioactive mineral grains penetrates the diamond. The radiation knocks carbon atoms out of their position in the diamond crystal lattice, and that defect causes the diamond crystal to selectively absorb red light and selectively transmit green. Green color can also be a result of defects produced by the presence of nitrogen, hydrogen, or nickel within the diamond crystal.
Orange diamonds are very rare. The defect(s) that produce the orange color have not been determined with certainty and may vary from one orange diamond to another. The defects in orange diamonds cause them to selectively absorb blue light and selectively transmit orange.
Purple is another rare color in diamond. In a study of 50 purple diamonds , they often found H3 and N3 color centers, sufficient enough to influence color. Purple diamonds and some pink diamonds modified by purple often exhibit color concentration along glide planes of carbon atom displacement.
Red diamonds are extremely rare in nature, and they are the most valuable diamonds when in a pure hue. Like pink diamonds, they have been subjected to stress which deformed the diamond crystal lattice, causing glide planes of carbon atom displacement. When light passes through the planes of displacement, the red wavelengths of light are selectively transmitted. Weak transmission of red light will produce a pink diamond.
Black diamonds with a natural color usually contain such a high density of mineral inclusions that very little light passes through the gem. Common inclusions in black diamonds include graphite, pyrite, or hematite. Black color in heavily fractured diamonds can be caused by graphitization of the fracture surfaces.
A diamond cut is defined as a shape of the stone, design, and style of the diamond. Although to most people all diamonds are the same, the reality is much different. Diamonds come in a plethora of shapes and sizes. While some diamond cuts are brilliant and sparkly, there are also those that are not. Also, some cuts work better when used as a side stone paired with another diamond, but others work entirely on their own. Throughout the history, diamonds and their cuts changed and evolved, and now there are different types of which some have become more popular than others.
In order to understand how different diamond cuts differ, it is essential to learn more about the anatomy of these stones. A diamond contains two primary sections called crown and pavilion. The relationship between two sections has an impact on brilliance and sparkle of the stone. As you can already conclude, the crown is the top part while pavilion is the bottom part. Other parts of diamond’s anatomy include :
- Facets – the surfaces of a diamond that can be polished
- Table – largest facet at the top
- Culet – facet located at the bottom tip which is not always visible to the naked eye (preferable)
- Depth ratio – height of the stone when measured from table to culet
- Girdle – narrow band found on the widest point of a diamond
- Diameter – width of a diamond when measured through the girdle
Different diamond cuts have a different number of facets, ratio, and other features that make them either brilliant or they provide some effects which are described below.
Different Types of Diamond Cuts
Diamond cutting has a long history that can be traced back to the Middle Ages. Before that time, diamonds weren’t used as jewelry, but starting with the Middle Ages things changed, and these stones became a symbol of power, elegance, marriage, and desire. Jewelers began shaping, i.e., cutting diamonds to make them more appealing. Kings used diamonds to woo their mistresses. For many years, these stones were closely tied to monarchies across Europe and other wealthy people. Today, diamonds have become accessible to all. Diamond cutting evolves constantly. As new methods emerge, cutters and jewelers get yet another opportunity to make stones prettier and shinier. In fact, brilliance and sparkle of the diamond depending on the cutting method.
Although there are many methods of diamond cutting, they can be divided into two categories: brilliant and a step cut. Brilliant cut is a rough diamond that was cut and polished in stone with outstanding brilliance. At first glance, this stone looks like a very polished cone. On the other hand, step cut is a diamond that has a rectangular or square shape, but facets are arranged parallel to one another.
We can divide diamond cuts to several types including: Princess, Cushion, Asscher, Radiant, Emerald, Round, Oval, Marquise, Pear, Half Moon, Triangle, Straight Trillion, Curved Trillion, Calf, and Heart cut.
The princess cut is a square-shaped diamond with a rounded top, and it is one of the most popular cut shapes on the market. This particular cut has been created in the 1960s, but the term “princess cut” was used to refer to another diamond, “profile cut,” created by London cutter Arpad Nagy. Many other jewelers and cutters used the term “princess cut” for their diamonds, but the name was made popular in 1979 by Israel Itzkowitz in Israel who is credited as the creator of the “princess cut” we know today.
The princess cut diamond has either 57 or 76 facets with an average ratio of 1.0 to 1.5, and it is well-known for its pyramidal shape which reflects light brilliantly thanks to four beveled sides. As a result, princess cut diamonds can be incredibly shiny. Compared to a round cut, princess cut diamonds look larger in size due to the square shape. The princess cut diamonds are a popular choice for engagement diamond rings and earrings. It is important to mention these diamonds tend to be referred to as Square Modified Brilliant on the certificate.
Cushion cut diamond has a square or rectangular shape, and its corners are rounded. The sides of these diamonds are curved, not straight and their outline is similar to that of a pillow hence the name cushion cut. This diamond shape has a long history. Similar diamonds appeared in the 1400s, but it took 400 years, in 1800s, for the term pillow cut to be used, but some jewelers also called them candlelight diamonds. In the 1900s, these stones got a more modern name – cushion cut. Since cushion cut diamonds were created before round cut stones, for many years, they were considered a standard.
Cushion cut diamond has 58 facets with ratios 1.00-1.05 for square shapes and 1.10 or more for rectangular shapes. Large facets create a greater separation of white light to spectral colors in cushion cut diamonds. Greater dispersion of light through the stone has a purpose of hiding inclusions more efficiently which explains why cushion cut diamonds are more brilliant than a vast majority of rectangular- and square-shaped stones.
The Asscher cut diamond shape was created in 1902 by the Asscher Brothers from Holland. There are two types of Asscher cut diamonds: standard Asscher cut and Royal Asscher cut both of which were designed by the same company. The latter is rare. This stone has a unique shape and a prismatic brilliance with a rectangular-faceted pavilion similarly to the emerald cut. Standard Asscher cut diamonds have 50 to 58 facets, but the royal type has up to 74 while the ratio is between 1.00 and 1.05.
What makes these diamonds unique is their ability to create the “hall of mirrors” effect thanks to the deep pavilion, high crown, faceted culet, and a small table which allow outstanding luster and create the optical illusion.
It’s not uncommon for people to assume Asscher cut and Emerald cut diamonds are the same thing, but they’re not. The main point of difference is the shape. While the top view of Asscher cut is square, the emerald cut has a rectangular top view look.
Radiant cut is one of the most beautiful diamond cuts one can find, and it was designed in 1977 by Henry Grossbard from the RCDC (Radiant Cut Diamond Company). Before this diamond shape was created, all diamonds were square cut with lower brilliance. Grossbard invented a hybrid diamond that revolutionized the diamond industry by creating a step-cut stone that is comparable to triangular-faceted diamonds.
Radiant cut diamonds genuinely live up to their name thanks to their shine. These diamonds can be rectangular or squared in edges. Rectangular radiant cut stones have ratios between 1.05 and 1.50 while squared stones have ratios between 1.00 and 1.05. Radiant cut diamonds have about 70 facets.
Due to its unique shape, radiant cut offers depth and brilliance comparable to princess and emerald cuts. That is why this stone is a popular choice for different jewelry types. Radiant cut diamonds hide inclusions more efficiently than other types of stones.
Emerald cut stones are one of the oldest diamond shapes with origins tracing back to 1500s. Back in time the term “table cut” was used to refer to these diamonds. The Art Deco period marks the onset of “emerald cut” term origin that is used today. Emerald cut stones have a rectangular shape, broad and flat plane, truncated corners. When viewed from above, the emerald cut stone looks like stair steps. Generally, this diamond cut features 57 facets of which 32 are on
the pavilion, and 25 are found on the crown.
Most emerald cut stones have ratios in a range between 1.30 and 1.50, but the most popular ratio is 1.40. If you want a square emerald cut, then you should opt for lower ratios, while higher ratios are the stones of choice for buyers who want a rectangular cut. Compared to other cuts the Emerald cut stone has less brilliance, but its natural crystalline rectangular growth and clarity are highlighted by the broad flat plane.
Round cut is the most popular diamond shape. What’s more, about 75% of sold diamonds account for round cut stones. The history of this cut takes us back to the 17th century when jewelers and diamond cutters started using more complex ways to make sure stones look more refined. Three most important types of round cuts are Mazarin cut originating in 1650, Peruzzi cut from 1700, and Tolkowsky cut from 1919.
Round cut diamonds have 58 facets divided between girdle, crown, and pavilion. The ratio of this stone ranges between 1.00 and 1.02. Due to the fact that the cut naturally follows diamond crystal, it has an outstanding shine. Round cut diamonds have more brilliance and fire compared to any other shape. Plus, they are the most versatile diamond cut around fit for all types of jewelry and occasions. Round cut is a classic and timeless choice that never goes out of style, and it’s perfect for all buyers, especially bachelors, who aren’t sure what type of diamond to get to their significant other.
Oval cut stones belong to the group of the most beautifully cut diamonds that exude elegance and sophistication. Even though oval-ish stones were created about 200 years ago, history of the modern oval cut starts in the 1960s. Lead Russian cutter Lazare Kaplan is credited for creating modern oval diamonds. These stones have a rounded shape with 58 facets on average.
The ratio of oval cut diamonds varies from 1.33 and 1.66. Basically, if you want a longer oval shape, then you should opt for a larger ratio while more rounded stones have a smaller ratio. Oval stones elongate fingers while rounded stone minimizes the likelihood of the “bowtie effect.” When light that passes through the stone casts a shadow across central facets, it creates the bowtie effect, which is also found in pear, heart, and marquise cuts.
Bearing in mind that oval cut stones are cut in the same fashion as round diamonds, they have a wonderful shine, sparkle, and brilliance. An amazing benefit of oval cut stones is that they look larger than other diamonds of the same weight.
Marquise cut, also called Navette or a “little boat,” has elongated and pointed ends with a curved shape that resembles a football. The history of this cut starts in 1745 in Paris and, as you can already imagine, it was closely tied to the French monarchy. King Louis XV of France hired a jeweler to design a diamond that would represent his mistress’ smile. His mistress was Marchioness de Pompadour Jean Antoinette Poisson.
The regal stone usually features 58 facets of which 25 are on the pavilion, and 33 are found on the crown. The average ratio of these stones is 2:1, but they are also available in ratio ranges from 1.85 to 2.10. These diamonds are often cut to feature a “French tip” where the star and upper girdle facets replace large bezel facets. Marquise cut stones can sometimes suffer from a bowtie effect. Similarly to oval stones, marquise cut can elongate the finger and appear larger than other diamonds of the same carat weight. In order to avoid bowtie effect, it’s practical to opt for more shallow stone.
Half Moon Cut
Half moon also referred to as crescent, cut is a half-oval and half-round shaped diamond with a straight edge. This diamond is commonly used as a side stone which is why it is sold in pairs. Half-moon cut complements other cuts as rectangular, oval, and cushion cut stones perfectly. They also look great when used as a side stone surrounding princess cut diamond.
Back in time, half moon cut diamonds were cut from broken oval and round stones. They had a step cut similar to that of triangular stones, but today things are different. Nowadays, half moon stones are cut directly from the rough as jewelers and cutters use similar procedures for shaping round and oval diamonds. The change of a cutting style allows half moon stones to be brighter and sparkly. The ideal ratio for these stones is two because higher values result in a diamond that appears skinny. On the other hand, lower ratio produces a shrunken look.
Pear cut diamond is a combination of round and marquise stones. The very first diamond of this kind appeared in the 1400s, and it was created by a Lodewyk van Berquem of Bruges, a Flemish cutter and an inventor of scaif or the diamond-polishing wheel. At first, the term Pendeloque or Briolette Cut was used to refer to these stones. The pear cut diamond usually features 58 facets, and it has a ratio of 1.50 to 1.70. Similarly to marquise diamonds, pear cut stones may come with a French tip and they can suffer from a bowtie effect.
The elongated shape of a pear cut diamond creates a slenderizing effect on a finger and makes a wearer’s hands more elegant. Due to a variety of stone widths available, pear cut diamonds belong to the group of the most customizable stones. The ideal pear cut diamond has a rounded base and polished girdle.
Triangle, also known as trillion, cut diamonds have a triangular shape and their unique appearance varied through the years. First stones of this kind appeared in the 1400s, but modern-day triangle cut was designed in 1962, and it featured straight sides while another version appeared in 1978 by a jeweler Leon Finker in Amsterdam. The triangle cut diamonds usually feature 31 to 50 facets and a 1.00 ratio. What makes these stones unique is their versatility.
Similarly to half moon cut diamonds, triangle-shaped gems can be used as side stones to complement larger ones in the engagement ring or another piece of jewelry. That being said, triangle cut diamonds can also look amazing when using as solitaire stones on their own. Triangle cut diamonds hide inclusions well and have fantastic brilliance. When buying these stones, it’s important to consider depth. Inadequate depth takes away brilliance and sparkle from the stone.
Straight Trillion Cut
Straight trillion cut is, basically, an original form of triangle cut diamond. When triangular stones first appeared, they had straight edges, but more designs have a more curved appearance. Straight trillion cut can have between 31 and 50 facets, but the average number is 44. These stones have a ratio of 1.00; bearing in mind straight trillion stones are cut from a flat and vaguely triangular shaped rough diamond called macles it usually has a relatively shallow depth. It is commonly used as an accent stone.
Due to a somewhat shallow depth, straight trillion cut doesn’t sit too high on the finger and is suitable for practical brides who prefer simple jewelry. An amazing advantage of straight trillion cut is that it looks larger than it, actually, is. For this reason, it can be a great choice for bachelors on a budget who still want to make sure their fiancé or wife to be has a large-looking diamond on her finger.
Curved Trillion Cut
Curved trillion cut diamond is, essentially, a curvy variation of triangle stone. These stones are characteristic for modern triangle diamonds mainly because these stones had straight edges in the past. Thanks to its 31 to 50 facets, curved trillion cut has the sparkle that complements the angular shape. The exact number of facets depends on whether curved trillion is used to complement a larger solitaire diamond as a side stone or it is used as a solitaire stone itself. A typical ratio is 1.00.
It can work both ways, and this perfect versatility is the reason behind a growing demand for this diamond. Curved stones are employed for solitaires and feature amazing brilliance when cut to a proper depth. Similarly to straight cut trillion, this stone looks bigger than it really is. It can work perfectly in engagement rings, but it is also sold in diamond-studded earrings, solitaire pendant necklaces, and other types of jewelry.
Calf cut stone is a modified trapezoid. While the standard trapezoid diamond has four sides with top and bottom parallel while other sides are slanting inward, calf cut has an extra side that makes it more interesting. At first glance, the stone resembles a calf’s head hence the name of this diamond. Calf cut stones are relatively rare which only adds to their uniqueness. While most of them are brilliant cut, some jewelers use a step cut method.
The ratio and number of facets depend on the type of the cut used for that particular diamond. These stones are commonly used as complementary stones that accentuate some other center diamond shape. Recently, they gained on popularity. Calf cut is a great alternative to trillion cut stones, and it usually has a greater depth, thus giving more sparkle. If you want more shine, then opt for brilliant cut stones, while step cut works perfectly when used as a side stone with another diamond that was also step cut.
Heart cut diamonds are romantic and elegant. While the history behind this type of stone is unknown, it is assumed the first heart-shaped diamonds appeared in the
16th century. The first exact record associated with this diamond dates back to the 17th century, 1605, when it appeared in a portrait “The Gonzaga Princess” painted by Frans Pourbus junior. In the 1900s, heart cut diamonds get the modern-day shape that is still used.
The heart-shaped diamond has 56 to 58 facets and a ratio between 0.90 and 1.10. These stones may have French tips, and they can suffer from a bowtie effect. When buying heart cut diamonds, the most important thing to consider is quality of the curved cut. The quality of curved cut determines the brilliance and sparkle of the stone. Only talented jewelers and cutters have necessary skills to make these gems have a heart-shaped curvature that makes them look so pretty.