Diamond Knowledges
IGI - Certificate
The most authoritative diamond grading institution in the world is the Gemological Institute of America (GIA). In addition to GIA, there are several other well-recognized gemological laboratories: HRD Antwerp (Hoge Raad voor Diamant) – Belgium's High Council for Diamonds IGI (International Gemological Institute) AGS (American Gem Society) EGL (European Gemological Laboratory) NGTC (National Gemstone Testing Center of China)
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HRD - Certificate
The HRD certificate is a diamond grade certificate issued by the Belgian Diamond High Council. What is the Belgian Diamond High Council? As the world's diamond trade center, Antwerp, Belgium established the Diamond High Council--HRD (Belgian Diamond High Council) in 1973. Its main work is to coordinate the activities of the Belgian diamond industry. After years of development, HRD has become an official organization recognized by Belgium and the world, serving as the organizer, spokesperson and media of the Antwerp diamond industry. It is also one of the most authoritative diamond inspection, research and certificate issuing institutions in the world, and is the highest official management organization of the diamond industry in the world's largest diamond trading place (Antwerp, Belgium). HRD is also at the forefront of the world in diamond processing and testing technology and equipment research. For example, the artifact in the link below was developed by HRD! 给我一颗钻，5秒便能辨真假 Now let’s have a look at their certificate! The section mainly consists of basic information about diamonds and the 4Cs 1. HRD logo 2. Certificate Number: HRD certificate number 3. Antwerp, March 25, 2010: location and time of certificate issuance 4. Shape: cutting shape For an introduction to round diamonds, click on the article below! 圆钻有话说！ You can click on the article below for more shapes! 你们都买圆钻？我偏不！ 5. Carat（weight）： Carat is the unit of diamond weight, called "克拉" in Chinese. 1 gram = 5 carats, 1 carat = 100 points 你所应该了解的关于4C的一切之克拉！ 6. Fluorescence： Diamond fluorescence refers to the emission of blue or yellow light or other colored light under strong ultraviolet light. According to the intensity level, it is divided into five levels: NONE, FAINT, MEDIUM, STRONG, and VERY STRONG. It cannot be felt under natural light. 7. Color Grade： Gem grade white diamonds start from D color to Z color. Diamond color starts with D, the first letter of Diamond, and is the whitest from D color, gradually turning yellow. The value also gradually decreases. 你所应该了解的关于4C的一切之颜色！ 8. Clarity Grade： Refers to the amount of inclusions in a diamond under a 10x magnifying glass. 你所应该了解的关于4C的一切之净度！ 9. Cut : Mainly look at three indicators: polish, cut proportion and symmetry Cut is very important for a diamond, it directly affects the brightness of the diamond. Even the best color and clarity diamond will be dull if the cut is not good. Grades are divided into EXELLENT (abbreviated as EX) VERY GOOD (abbreviated as VG) GOOD (abbreviated as G) FAIR 你所应该了解的关于4C的一切之切工！ 10. Proportion： The cutting proportion of a diamond will affect the reflection of light entering the diamond, which will further affect the fire of the diamond. 11. Polish： Polishing will increase the brightness of the diamond. After the diamond is cut, it must go through a polishing process to make the surface of the diamond smooth. A polished diamond is relatively brighter and will not affect the refraction of the diamond's fire. 12. Symmetry： Symmetry refers to whether a diamond is cut symmetrically on both sides. Since all diamonds have a maximum and minimum diameter, no diamond is completely symmetrical. ================================================ Below indicates: This is a 1.55 carat round diamond with medium fluorescence, F color, SI2 clarity, and VG, EX, EX cut. The following information are some technical info. 1. Measurements：size of diamond Diameter (minimum - maximum) * height The diameter is allowed to be a range, the unit is millimeter. The following information is the proportion data of the diamond 2. Girdle: Girdle Percentage 3. Culet: Culet 4. Total Depth: Total Depth Height Percentage 5. Table Width: Table Width 6. Crown Angle (β): Crown Angle 7. Pavilion Angle (α): Bottom Angle 8. Length Halves Crown: Half Length of Crown 9. Length Halves Pavilion: Half Length of Pavilion 10. Sum α&β: Sum of α&β Here, the clarity, cut and color grade table marks the 4C color of the diamond. Buyers can know at a glance what grade of the diamond they are buying. Here is the top view and bottom view of the diamond. If the diamond has obvious impurities or inclusions, they will be marked on the picture. Signature from the expert~ If you want to check the relevant diamond information, you can link to the HRD official website to check the certificate HRD certificate official website https://my.hrdantwerp.com/
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The difference between certificates
The difference between certificates Among the most recognized diamond grading certificates in the world today, one of the most prominent is the HRD certificate from Europe.But what does HRD stand for? HRD is the abbreviation of “Hoge Raad voor Diamant”, which translates to “High Council for Diamonds” in English. Based in Antwerp, Belgium, HRD represents the highest standard of diamond certification in Europe. As the first diamond grading institute to be ISO-certified, HRD sets a benchmark for accuracy, consistency, and integrity in diamond evaluation.This international recognition has made the HRD certificate a trusted symbol of authenticity and quality in the global diamond industry. How Did Diamond Certificates Come Into Existence? Since the 1970s, diamond investment has been a highly profitable industry. However, prior to that time, there was no universally recognized diamond certification system within the trade. It was in the early 1970s, when diamond investment began to gain popularity, that the demand for a reliable grading system emerged. As investment interest surged, so did diamond prices—especially for stones with higher color and clarity grades. Thanks to improvements in the trade structure of rough diamonds and a more transparent supply chain, the diamond market became increasingly secure. With prices steadily climbing, investing in diamonds grew even more appealing. This trend attracted not only traditional industry insiders, but also investors and entrepreneurs from outside the trade, who began exploring this emerging market. To boost diamond consumption, some organizations established a series of gemological laboratories and began issuing certificates aimed at inflating prices. These diamond labs began to spring up like mushrooms after the rain, each adopting its own grading standards and proprietary naming systems. However, these certificates offered no real assurance of quality or consistency. Most laboratories did not recognize each other's evaluations, resulting in a lack of uniformity and credibility. As a result, buyers often became the victims, unknowingly purchasing diamonds with overstated grades. The overall trust in diamond certification began to decline significantly. In 1972, the World Federation of Diamond Bourses (WFDB) and the International Diamond Manufacturers Association (IDMA) held an international congress in Antwerp to address the issue of diamond grading standards. However, the outcome of the meeting was far from promising. Diamond traders remained skeptical of the grading certificates, and even more concerning was the growing public doubt surrounding diamond standards—partly fueled by political interference. This lack of trust hindered the establishment of a unified and reliable certification system at the time. In 1974, the Hoge Raad voor Diamant (HRD), or the Diamond High Council of Belgium, approved the establishment of a certification office under the Scientific and Technical Research Center. The goal was to develop a verifiable and objective grading standard. This research was conducted in Antwerp, and the experience gained laid the foundation for later negotiations by a joint committee. At the same time, a document titled Project for Normalising the Specifications of Diamond was published. In 1975, the Diamond Council abolished many questionable standards and naming systems used by unqualified laboratories. A joint committee was established, composed of representatives from the World Federation of Diamond Bourses (WFDB) and the International Diamond Manufacturers Association (IDMA), to address the ongoing issues. The committee reached the following resolutions: A unified standard must be established that is recognized by international organizations. These standards must employ consistent methods and remain verifiable under all circumstances. Laboratories must be established and accredited by professional organizations affiliated with IDMA and WFDB. The standardized terminology and grading system developed by representatives from the joint committee of HRD and CIBJO (The World Jewellery Confederation) were officially accepted by other organizations after the conference. The original master copy of this diamond grading standard has been preserved in Antwerp. In order to fully evaluate the beauty of a diamond, all relevant details can be found in an HRD certificate. A certificate is only useful when it is trustworthy and widely recognized — the HRD certificate enjoys a strong reputation for its objectivity, reliability, and quality. In February 1996, the HRD certification department was awarded the ISO 9002 quality label for its grading of polished diamonds. Today, HRD diamond certificates are officially recognized by most countries and institutions around the world. If you purchase a diamond certified by HRD, you can verify the authenticity of your certificate by visiting the official HRD website at http://www.hrdantwerplink.be/ and entering the diamond’s carat weight and certificate number. In addition to HRD, there are several other internationally recognized diamond certificates, such as those issued by the Gemological Institute of America (GIA). GIA stands for the Gemological Institute of America. Founded in 1931, it is considered a later entrant compared to the Hoge Raad voor Diamant (HRD) in Belgium. At that time, many jewelers lacked a deep understanding of the gemstones they worked with. Recognizing this gap, a sharp-minded jeweler named Robert M. Shipley saw an opportunity and invested his life savings to establish GIA in Los Angeles. His goal was to provide professional training, gemstone grading services, and specialized equipment for the jewelry industry. Although the Gemological Institute of America (GIA) was established as early as 1931, its true period of rapid growth came after World War II, during the 1950s and 60s. This era marked a golden age of economic prosperity in the United States. As people became more affluent, they gained the financial means to purchase luxury items—such as diamonds. This economic boom ushered in a golden era for the diamond industry in the U.S., creating an urgent demand for a standardized, quantifiable method of evaluating diamonds. With foresight, GIA recognized this trend and, building upon previous knowledge, introduced the concept of the "4Cs." This framework provided a crucial theoretical foundation for the diamond trade. Although it has undergone refinements over the years, its core principles remain widely adopted in the industry today. As a pioneering organization in the standardization of gemstone grading, GIA was also among the first to promote diamond grading certificates to the general public. GIA’s certificates are known for their consistency and carry a kind of industrial elegance rooted in standardization. With its middle-class appeal and highly effective marketing, GIA gained widespread public recognition. Following HRD's entry into the Chinese market in the 1990s, GIA soon followed in the early 2000s and quickly became one of the most well-known and trusted international diamond certificates in China. To this day, GIA is widely recognized as one of the most rigorous and authoritative diamond certification institutions in the world. It has earned the trust of both the market and consumers. If you purchase a diamond with a GIA certificate, you can verify its authenticity by entering the report number found on the certificate at the official website: http://www.gia.edu/report-check-landing. After introducing HRD and GIA, let’s now turn to the third of the three major diamond certificates: the IGI certificate. IGI stands for the International Gemological Institute. Interestingly, IGI shares its roots with HRD, as both originate from Antwerp, Belgium—known as the “Diamond Capital” of the world. Although it is a heavyweight authority in diamond certification, IGI is considered the "younger sibling" compared to HRD and GIA. Founded in 1975, IGI emerged in the wake of the World Federation of Diamond Bourses (WFDB) and the International Diamond Manufacturers Association (IDMA) jointly deciding to clean up the market by eliminating low-quality and unreliable certificates. IGI’s mission from the beginning has been to provide a reliable certification platform for both diamond and jewelry industry professionals as well as consumers. IGI was truly born into a prestigious lineage. When it was first established in Antwerp, it offered private diamond grading services exclusively to a select group of Belgium’s most prominent diamond families. As some of these high-quality diamonds made their way into the collections of various European royal households, the name IGI began to quietly gain recognition among royalty. Over time, IGI became the trusted solution for royal families across Europe, the Middle East, and Asia—especially when dealing with pre-set diamonds that were difficult to assess using standard methods. What began as a diamond grading institute gradually evolved into a renowned authority specializing in the certification of both loose diamonds and high-end jewelry. Compared to GIA, IGI serves a distinctly different clientele, which is reflected in the unique style of its certificates. From its inception, IGI catered primarily to elites, affluent collectors, and members of royalty. As a result, IGI certificates go beyond simply providing diamond grading information—they are crafted with the same artisanal care as luxury goods, designed to match the refinement and exclusivity of the diamonds themselves. Much like bespoke haute couture, each certificate is tailored to highlight the character of the piece it accompanies. This personalized, luxury-oriented approach has made IGI the preferred certification body for many high-end brands. For example, luxury houses like Dior and Montblanc often include IGI’s custom certificates with their diamond jewelry collections. Even celebrities such as Paris Hilton have turned to IGI, which graded the pink diamonds in one of her signature timepieces. Today, IGI has gradually shifted its market strategy and begun expanding into the broader consumer market. If you’ve purchased a diamond with an IGI certificate, you can verify its authenticity by entering the certificate number on the official IGI website at:http://www.igiworldwide.com/ch/search_report.aspx. We’ve now explored the three major diamond grading certificates—HRD, GIA, and IGI—and gained a general understanding of their origins. Although these organizations had different goals and market focuses when they were first established, the resolutions passed at the 1974 international meeting on standardized diamond grading laid the foundation for decades of integration, development, and unification. Today, all three institutions follow consistent and internationally recognized grading standards. Each certificate serves the same essential purpose: to provide a trustworthy, objective assessment of a diamond’s quality and to protect the rights of consumers. As professionals in the industry often say, “Rather than obsessing over which certificate to choose, it’s far more practical to spend that energy selecting the perfect 4C combination that speaks to you."
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What is Cut?
Cut is one of the most important standards in determining a diamond's value, as it reflects how the facets interact with light. Transforming a rough diamond into a finished gem involves intricate processes, exceptional craftsmanship, and meticulous polishing—only then can a diamond’s unique brilliance be fully revealed. This is why professionals refer to it as: Brightness: The white light reflected from both the internal and external surfaces of the diamond. Fire: The dispersion of white light into a rainbow of spectral colors. Scintillation: The sparkle a diamond produces, along with the pattern of light and dark areas caused by reflections within the stone. Cut is critical to both the appearance and value of a diamond. Among the 4Cs, it is the most complex and technically demanding to assess. Cut grading includes three components—Cut, Polish, and Symmetry—each evaluated on a scale of four to five levels: Excellent (EX), Very Good (VG), Good, Fair, and Poor. When a diamond receives an Excellent grade in all three categories—Cut, Polish, and Symmetry—it is known as a Triple Excellent (3EX) diamond, representing the highest standard of cut quality. What exactly do Cut, Polish, and Symmetry each refer to? Cut refers to the proportions between the different facets of a diamond. It’s much like the body of a model—being tall alone isn’t enough; true beauty lies in the harmonious balance of all body parts, achieving a golden ratio that highlights physical elegance. Polish describes the surface condition of the diamond after cutting, including any marks or abrasions. Just like flawless skin enhances a person’s beauty, a diamond’s surface should be smooth and free of blemishes. Symmetry, as the term implies, refers to the precision of the diamond’s geometric shape after cutting. It evaluates how well the facets are aligned and balanced in relation to one another. But is it always necessary to pursue a 3EX diamond when buying? First, let's take a closer look at how diamond cut grading is determined. Over a decade ago, diamond cut grading was based on the trained eye and extensive experience of gemologists. However, things have changed. With the advancement of computer technology, the task of grading diamond cuts is now largely performed by computers, making the evaluation process much more precise and consistent. When a diamond is placed into a 3D scanner, the computer analyzes the scan data according to established cut grading standards to produce a grade. Thanks to advances in computing power and scanning accuracy, cut grading has become increasingly precise. From another perspective, this means that although diamonds of different cut grades can vary greatly in price, their numerical scores and visual appearance may actually be very similar. In fact, before 2006, the diamond market did not even have an Excellent (EX) cut grade—the highest grade at that time was Very Good (VG). With technological advancements, the standards were raised, and the Triple Excellent (3EX) grade was established as the highest benchmark. In short, while 3EX diamonds represent the very best quality, diamonds that are not 3EX are not necessarily inferior. Comparison chart of diamond cuts under normal visual conditions Comparison of the appearance of three diamond cut grades under a cut grading scope When it comes to cut, many people might wonder, "What exactly is ‘Hearts and Arrows’?" In much commercial advertising, “Hearts and Arrows” is often highlighted as a major selling point. But is it really that unique? In fact, as long as the cut is not poor, almost every diamond will display the Hearts and Arrows pattern. For example, in the image below, diamonds with Excellent (EX), Very Good (VG), and Good cut grades all show the Hearts and Arrows pattern clearly. However, at the Good level, the pattern starts to look a bit distorted. What exactly does cut shape refer to? Cut shape simply refers to the geometric form in which a diamond is cut. There are many different shapes available on the market, but the most common is the round cut (also called Round or Solitaire), which accounts for about 80% of the market. The princess cut is the second most popular shape. Other common shapes include marquise, cushion, emerald, asscher, heart, pear, radiant, and oval cuts, among others. Every woman has her own unique body features, which means each has distinct hand and finger shapes. Just as not every piece of clothing suits every body type, not every diamond shape complements every hand or finger shape. Each hand shape pairs best with certain diamond cut shapes. Among all the cut shapes mentioned above, the round cut is probably the most versatile, adapting well to a wide variety of hand shapes. This versatility is likely a key reason for its popularity. The 57-facet round brilliant cut is considered the most perfect shape and has been continuously refined over the past century. Cushion-cut diamonds share similar qualities with round cuts, but their suitability largely depends on the size of the stone itself. If you have any questions about diamonds, please feel free to contact us via email or WeChat—we will be happy to assist you as soon as possible.
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What is fluorescence?
Fluorescence refers to a diamond's ability to emit a visible glow—typically blue—when exposed to ultraviolet (UV) light. Approximately one-third of natural diamonds exhibit some degree of fluorescence. Under UV light, these diamonds can show varying intensities and hues of fluorescence. The Gemological Institute of America (GIA) classifies fluorescence into five levels:None, Faint, Medium, Strong, and Very Strong. Fluorescence in diamonds primarily affects two aspects: Fire and Transparency – Stronger fluorescence may cause a diamond to appear slightly hazy or less transparent under certain lighting conditions. Apparent Color – In some cases, fluorescence can make diamonds, particularly those in the H-color range or lower, appear whiter or brighter to the naked eye. It's important to note that fluorescence does not mean the diamond itself is blue. Diamond color grading is based on the presence of yellow or brown tints in normal lighting, not on fluorescence color under UV light. Generally speaking, fluorescence has little to no impact on a diamond’s wearability. In fact, recent academic studies suggest that fluorescence can have positive effects, making lower-color diamonds appear whiter under everyday lighting conditions. This optical benefit can enhance visual appeal while also offering better value for budget-conscious buyers.
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What is Clarity
Many people often get caught up in worrying about a diamond’s clarity when making a purchase, thinking that if they’re spending so much money, they should at least get a diamond with a clarity grade of VS or higher. I believe that if money is no object, aiming for the highest color and clarity grades is a sure way to avoid any regrets. However, this approach isn’t practical for everyone. Most people have a limited budget, so the question becomes: how can you get the best value for your money when buying a diamond within a budget? First of all, it’s essential to understand how diamond clarity is graded, as this knowledge is very important when choosing a diamond. Clarity directly relates to the inclusions inside the diamond. Factors such as the location, number, size, color, orientation, and visibility of these inclusions all affect a diamond’s clarity grade. According to widely accepted grading standards, clarity is divided into eleven different levels. Among all the clarity grades, the highest is called Flawless (FL). Diamonds with this grade are completely free of any inclusions or blemishes, making them truly exceptional and rare. The next grade is called Internally Flawless (IF). Diamonds in this category have no internal inclusions, with only very minor blemishes on the surface or edges. The next level is called Very, Very Slightly Included (VVS1/VVS2). For the grades Flawless (FL), Internally Flawless (IF), and Very, Very Slightly Included (VVS1/VVS2), only highly experienced gemologists can detect inclusions under 40x magnification. Next comes the Very Slightly Included (VS1/VS2) grade. Diamonds in this category can be seen to have inclusions only with difficulty by experienced gemologists using a 10x loupe and 40x microscope. Next is the Slightly Included (SI1/SI2) grade. Diamonds in this category have inclusions that trained gemologists can observe using a 10x loupe. From IF, VVS, VS to SI, the inclusions in these four grades are not visible to the naked eye. The lowest grade is Included (I1/I2/I3), where inclusions are visible to the naked eye without any magnification. In terms of value, diamonds with higher clarity grades naturally command higher prices. However, flawless natural diamonds are extremely rare because during their formation, it’s nearly impossible to avoid the intrusion of other materials due to external environmental factors. The only thing that can be done is to carefully cut away the parts with more inclusions during the cutting process, preserving the clearer sections of the rough stone. This scarcity is what makes high-clarity diamonds so valuable. For those with a limited budget, is it really necessary to choose a diamond with high clarity? Most people buy diamonds to wear, not to keep locked in a safe. Let’s take a look at how diamonds of different clarity grades appear under 10x magnification and after they are set in jewelry. Clarity comparison chart under 10x magnification We can see that diamonds of different clarity grades show little difference in appearance once set and worn. Generally, the comfortable distance between people is about one meter, at which point the visual difference in clarity becomes even less noticeable. So, how big is the price difference? A 1-carat, D color, IF clarity diamond is priced internationally at around $27,500. A 1-carat, D color, SI2 clarity diamond is priced at about $7,100. This clearly shows that, regardless of the subtle visual differences, the price gap is significant and easy to notice.
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What is Color?
Most diamonds are either colorless or with a slight yellow tint. However, diamonds can also occur in a variety of other hues, such as red, blue, or pink—these are known as fancy colored diamonds. In terms of traditional white (colorless) diamonds, the highest color grade is D, which represents complete colorlessness. This is followed by grades E, F, G, H, I, J, K, and L, with each successive grade showing an increasing presence of yellow or brown tones. The further down the scale, the more noticeable the color becomes. Grading a diamond's color is an extremely delicate process, especially for the higher color grades such as D, E, and F. Accurate color determination can only be made in a fully enclosed darkroom within a professional gemological laboratory, using a diamond light with a color temperature of 6500K. Under such controlled conditions, experienced gemologists compare the diamond to master stones in order to assign the correct color grade. Once a diamond is set in jewelry, however, and viewed under natural daylight, even trained eyes may find it difficult to distinguish between grades like D, E, and F—let alone tell the difference between lower grades such as I, J, or K. For the average person, the color variations are often subtle and barely noticeable. After 20 years of experience in the industry, I’d like to share a small but valuable tip. Below is a comparison of three set diamonds we selected—D color, H color, and J color. The first group of photos was taken under laboratory lighting conditions, and as you can see, the color differences are minimal. The second set of photos shows how the diamonds appear under regular lighting in everyday wear—and the difference is almost imperceptible. If you're with a limited budget, there's no need to obsess over top color grades. Once a diamond is set, the visual difference in color becomes very subtle. Instead, consider allocating more of your budget toward a larger carat weight, which will give you a more noticeable visual impact. 除了常规颜色的钻石以外，最近成为热门话题的还有各种彩钻。 例如日前在苏富比拍卖会上创造纪录的粉红之星，则不在传统的颜色分级当中。彩钻的颜色有自己的分级标准，根据其颜色的浓度可以被分为 In addition to traditional colorless diamonds, fancy colored diamonds have recently become a hot topic. For example, the Pink Star, which broke records at a recent Sotheby’s auction, falls outside the standard color grading scale. Colored diamonds follow their own grading system, which is based on the intensity of their color. Depending on the depth and vividness of the hue, they are typically classified into the following categories: Faint→Verylight→Light→Fancylight→Fancy→Fancydark→Fancyintense→Fancyvivid→Fancydeep 尽管深彩在所有彩钻中是颜色最浓的，但是艳彩的视觉效果才是最绚烂的，也是所有彩钻中价值最高的等级。 Although Fancy Deep diamonds show the deepest color saturation among all fancy colored diamonds, it is the Fancy Vivid grade that delivers the most brilliant and striking visual effect. As a result, Fancy Vivid is considered the most valuable grade among all fancy color diamonds. How are fancy colored diamonds formed?Different causes result in different diamond colors: When nitrogen atoms replace some of the carbon atoms in the diamond's crystal structure, yellow diamonds are formed. When boron is absorbed, the result is a blue diamond. If the diamond's crystal lattice is distorted, it can produce pink or green diamonds, depending on the specific type of distortion. Black diamonds, on the other hand, owe their color simply to being filled with dark inclusions. According to statistics from experts, for every 100,000 gem-quality diamonds mined, only one might be a fancy colored diamond—a rarity with an occurrence rate of just 1 in 100,000. Among fancy colored diamonds, yellow, brown, and green are relatively more common. Others like pink, red, and blue are extremely rare and often considered once-in-a-lifetime finds.
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What is Carat
The weight of a diamond is measured in carats (ct). The term carat originates from the Greek word "keration", referring to the seeds of the carob tree, which grows in the Mediterranean region. These seeds were historically used to weigh precious gemstones because of their remarkably uniform size and weight, and the term has been carried over into the modern gemstone industry. In standard units: 1 carat = 0.2 grams 1 carat = 100 points Diamonds heavier than 1 carat are typically expressed in carats (e.g., 1.25 ct), while diamonds weighing less than 1 carat are often referred to by "points" (e.g., 0.25 ct = 25 points). In general, the heavier a natural diamond is, the higher its price. However, the relationship between price and weight is not a simple linear one. In diamond valuation, there’s an important concept called the carat premium. This refers to the sharp increase in price that occurs when a diamond reaches a key milestone weight—typically a full-carat mark (such as 0.50 ct, 1.00 ct, 1.50 ct, etc.). These weight thresholds trigger a step-like price jump, even if the increase in weight is minimal. This phenomenon is what’s known as the carat premium. Let’s take an example:Two diamonds with the same specifications—D color, IF clarity, and the same cut grade. One weighs 0.99 carats, priced internationally at $15,500 per carat. The other weighs 1.00 carat, priced at $27,500 per carat. Now let’s calculate: 0.99 ct × $15,500 = $15,345 1.00 ct × $27,500 = $27,500 The difference in weight is just 0.01 carat, but the price difference is a staggering $12,155! For most consumers who don’t handle diamonds often, it’s hard to have an intuitive understanding of how weight translates to visual size. So, how big do diamonds of different carat weights actually look when worn? The image below illustrates the appearance of round diamonds of various weights when worn on the finger:
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