The History of Diamonds

Diamonds have been revered and treasured for thousands of years. Originally discovered in India around 3000 BC, they were valued for their luster as natural crystals and for their virtual indestructibility. It is no surprise that diamonds became associated with beauty, strength, and longevity by early humans. The early history of diamonds has been chronicled extensively in acclaimed works such as Diamonds: An Early History of the King of Gems.

In this article we will focus on the modern era of the world’s fascination with diamonds. From the turn of the twentieth century to the first quarter of the twenty-first there have been many interesting and sometimes revolutionary developments in our understanding and appreciation of diamonds, and major events impacting the diamond market. To a very large extent the evolution of the diamond market in the last few decades is not well known outside the diamond trade. We will dig into some of these events and discuss how they have impacted, and in some cases upended, our views on the King of Gems.

At a glance, here is what reshaped the modern diamond era:

• The 4Cs and lab reports become the shared language of the global trade.
• For decades, cutters optimise weight yield over beauty, even when better optics are known.
• De Beers builds demand with “A Diamond is Forever”, reshaping engagement culture.
• The internet changes everything: shoppers buy by report plus images, not by trust alone.
• Cut quality becomes measurable: AGS light performance, later integrated into GIA services.
• Lab grown explodes in the 2010s and 2020s, forcing new grading and new messaging.
• Kimberley Process addresses conflict sourcing, but enforcement must remain vigilant.
• GIA shifts lab grown reporting toward category-based assessment (“Premium” and “Standard”).

The modern era is often associated with the work of Belgian mathematician Marcel Tolkowsky and his publication of a thesis on diamond cutting based upon the immutable physics of light in 1919. For bringing these insights to a worldwide audience he is often considered the Father of the Ideal Cut. But diamond cutters in the latter part of the 19th century, particularly in the United States, were already cutting diamonds to proportions very similar to those Tolkowsky posited as producing the most beautiful light performance. Al Gilberson’s fascinating look at the history of the American Ideal Cut chronicles the work of those diamond pioneers. As we will see, they were very ahead of their times; it would be another hundred years before the diamond manufacturing industry began to embrace the concept of cutting for maximum beauty.

But the beginning of the modern era in the history of diamonds can be legitimately pinned to the establishment of the Gemological Institute of America (GIA), and a lot has happened since then!

To understand how these developments unfolded, it helps to see them chronologically:

The Gemological Institute of America (GIA) was established in 1931 by Robert Shipley and his wife Beatrice for the purpose of educating and training jewelers. In 1934 he also founded the American Gem Society (AGS) for the purposes of promoting ethical practices in the jewelry trade.

In 1953 the GIA introduced the revolutionary diamond 4 Cs grading system developed by Richard Liddicoat. It would go on to be adopted as a global standard of diamond grading. In 1955 the GIA began issuing diamond reports which would become the gold standard worldwide.

Early diamond cutting factories such as those in Amsterdam paid their cutters based on the amount of carat weight yield they could extract from the rough that was given them. This set the stage for cutting for weight that would persist over the next several generations. This mentality was brought to the US and greatly influenced its fledgling diamond industry. So ingrained was this practice that it is still a significant factor in diamond manufacturing today, even as scientific information was available in the early twentieth century demonstrating that to cut the most beautiful diamonds proportions should be in a narrow range that would reduce carat weight yield.

Following the 1867 discovery of diamonds in South Africa, Cecil Rhodes bought up mining claims, including those of brothers Diederik and Johannes de Beer. The company would become formally known as DeBeers and would drive and shape the diamond industry for decades, exerting monopolistic control for much of that time.

In 1947 DeBeers coined the phrase A Diamond is Forever as part of an iconic marketing campaign that coupled a diamond’s beauty and durability with the beauty and longevity of marriage. A growing post-war middle class would adopt diamond as THE symbol of engagement and marriage resulting in a boom for the diamond trade.

Prior to the “information age” and the introduction of scientific cut grading in the 1990’s, the 60/60 cut was considered the rule of thumb for a well cut round diamond. This was often misleading as there are multiple ways the geometry of a diamond can achieve a 60% table and 60% depth. But good examples of this proportion set were very bright and spready and this simple rule came to dominate, at least until the time of ray tracing analysis.

As interest in cut quality increased in the information age, so did interest in older facet arrangements and cutting styles. Interest in Old Mine Cut diamonds, one of the earliest cut styles featuring more than just a few crude facets, as well as later Old European Cut diamonds and Transitional cuts that formed a bridge to the 57 facet Modern Brilliant Cut, all began to receive additional attention from consumers. The type of light performance characteristic of these earlier cuts, particularly their ability to generate large colored sparkles (diamond fire), gained attention and attracted new admirers.

When 4Cs grading was established the main purpose of a diamond report was to positively identify the diamond, as well as determine quality in key attributes, mainly color and clarity. Because many diamonds have a property known as photoluminescence, commonly referred to as fluorescence, and that the trait could be observed in a range of strengths and colors under special lamps, it was added to 4Cs grading as another important datapoint that could help identify an individual diamond. Fluorescence would later become controversial as the market began to see it as a quality factor. In early times certain diamonds that were colorless and had strong blue fluorescence were seen as unique and superior. The term “Blue White” was used by diamantaires to describe these elite gems. But the term began to be abused by the trade and applied to virtually any diamond with strong blue fluorescence, including stones that were milky or oily as a result of the trait. The problem was so significant that the Federal Trade Commission instituted new rules on the use of the term. More recently, with much shopping being done on the internet and based almost solely on the diamond report itself, many buyers eschew strong fluorescence in order to avoid the risk of getting a diamond with a fluorescence-related transparency problem.

Prior to the emergence of fully synthetic diamonds, technological advances had brought a number of treatments into the market including irradiation to induce color into natural diamonds, high pressure and high temperature treatment to de-colorize them, fracture filling techniques to enhance their apparent clarity, and laser drilling to make inclusions less noticeable. Only the latter technique, laser drilling, found any significant degree of acceptance in the market. Fracture filled diamonds, also known as clarity enhanced diamonds, tend to be particularly avoided in the marketplace because the treatment is not permanent. The filling material can be altered by heat or other environmental factors or removed altogether by certain deep cleaning techniques.

All of these as well as other novel treatments can be detected at top tier laboratories during the identification and grading process.

In the 1990’s personal computing hit the mainstream. With it came the rise of e-commerce with companies like Amazon, demonstrating that consumers would buy products from the comfort of their homes through their keyboards. The early assumption was that consumers would buy products online only if they were under $50 and identical to products in stores that they were acquainted with, such as books and CDs. But it was not long before e-commerce companies were proving that almost anything could be sold online, including diamonds and jewelry. Advances in online imaging and the rise of the diamond “certificate”, primarily grading reports from GIA initially, propelled a whole new marketing channel that has grown to include some of the world’s major diamond manufacturers and storied designer jewelry brands.

The diamond grading landscape became crowded in the 1980s and 1990’s. One of the new entrants was the European Gemological Laboratories (EGL). This entity had a unique business model compared to other gemological institutions. They were an affiliated group of labs operating independently in various locations around the world under the EGL umbrella, but without central control of their operations. Eventually wide grading variances started to show up in a few of their labs that suggested either poor grading techniques or worse, ethical problems connected with very lenient grading. Ultimately, the reputation of EGL was tainted, and although some of the labs were doing excellent work, all suffered from the reputational damage - probably none more than EGL USA which always had a solid reputation in the industry.

In 1996 the American Gem Society, a sister organization to the GIA, established their own diamond grading laboratory (AGSL). The impetus was to provide special focus on cut quality analysis which was part of the GIA curriculum but not emphasized on GIA grading reports at the time. AGSL pioneered the concept of the Ideal Cut and their reports became popular with AGS member stores and the market as a whole. There was a growing interest in cut quality as the internet was starting to distribute information more widely about the importance of Cut to diamond beauty. Initially based upon parametric grading, the AGS Triple Zero became shorthand for top cut quality among knowledgeable trade members and consumers. The AGS system is a 0-10 scale where 0 is Ideal (zero deductions). Thus a ‘Triple Zero’ was a diamond with Ideal Polish, Ideal Symmetry, and Ideal Overall Cut Grade.

As demand grew for Ideal diamonds the researchers at AGSL engaged in deep research about light performance, and with the rapid advances in computing power at the time were able to develop a performance-based grading system using light ray tracing. In 2005 AGSL released their Light Performance Cut Grading System that would revolutionize assessment of cut quality and would eventually lead to GIA acquiring and implementing the technology in 2022.

One of the beauties of the AGSL light performance approach to cut grading is that the fundamentals could be used to develop cut grade scales for any diamond shape. Fancy cut grading had been stymied by the limitations of parametric grading systems as the interplay of facet design, proportions, length to width ratios, and specific facet angles is too complex to enable prediction of light performance by basic geometry alone. By the time GIA acquired AGSL technology several fancy shape cut grading frameworks had been developed. These have also since been deployed in the form of AGS Ideal addendum reports for qualifying fancy shape diamonds. It is likely that GIA will soon launch fancy shape diamond cut grading more broadly using this technology, incorporating an overall cut grade on standard grading reports.

GIA finally released a cut grading system for round diamonds in 2005. The system was still parameter based and was limited to rounds. Underscoring the lead in cut quality expertise that AGSL had , it was just the following year that AGS released its ray tracing light performance cut grading system that would also include fancy shapes. GIA’s new system was widely adopted despite many who objected to the very broad and forgiving nature of the Excellent category. Despite this failing, or perhaps because of it, the GIA Excellent cut became the default grade for a well cut round brilliant. Manufacturers now had a target to shoot for in cut quality that would help them sell diamonds, leading to an almost overnight improvement in the general cut quality of rounds in the market. The broad nature of the grade also provided room in the market for companies specializing in precision cut and super ideal diamonds to demonstrate their superiority and serve a growing market of shoppers interested in diamonds of elite light performance.

During the twentieth century new diamond deposits were discover in several countries on the African continent. Many in remote places where diamond crystals had eroded out of their host rock and could be found on the surface, particularly in river beds. These diamonds could be “mined” without mechanized equipment and became the domain of “artisanal” miners. Because they were decentralized and not under any form of regulation or protection, they were easy targets for armed militias could take over fields and the diamonds, often subjecting the miners to terrible brutality. These anti-government militias used the proceeds from the diamonds they stole to fund their violent campaigns to depose governments in power. The diamonds that came entered the market in this way were known as “conflict diamonds” or “blood diamonds”. Though artisanal mining was a small portion of all diamonds mined, and not all artisanal fields were commandeered by militias it was a serious problem that needed to be addressed and solved. Diamond mining countries came together with business and NGOs to form the Kimberley Process to certify diamonds entering the market had come through legitimate sources and were conflict free diamonds.

Diamond was first synthesized in 1953 by General Electric company. In the ensuing years further R&D continued towards the goal of commercial production. Initially, very small diamond crystals were produced at scale for the abrasives industry. Ultimately two different technologies were developed to produce jewelry grade synthetic diamonds – Chemical Vapor Deposition (CVD) and High Pressure High Temperature (HPHT). In the first part of this century gem quality synthetic diamonds, now referred to commonly as “lab grown” diamonds, began reaching the market and being sold into the jewelry trade. Their availability and affordability began to take market share away from natural diamonds. By 2020, as natural diamonds were suffering the effects of severe supply chain disruption due to a pandemic and sanctions on Russian diamonds, lab diamonds began a meteoric rise in popularity with prices dropping rapidly and quality and size both increasing as the growing technology was refined.

When lab diamonds became available in commercial quantities the growers positioned the product on an equal footing with natural diamonds and began marketing them with laboratory reports detailing the 4C’s of diamond quality. The International Gemological Institute (IGI) gained a significant foothold in the market, eventually setting up on-site grading services at major factories capturing cost efficiencies and rapidly gaining market share. By contrast, the number of GIA reports for lab grown diamonds has always been quite small considering their global reach and reputation. HRD was also a major player in the lab diamond reporting market. GCAL has filled a niche based on cut quality analysis of lab diamonds, but with a much smaller market share.

In 2024 the GIA announced that they would no longer be doing 4Cs grading of laboratory grown diamonds. Instead, GIA would render a “Quality Assessment Report” for lab grown diamonds that would assign one of two categories of quality deemed Premium and Standard. Only diamonds of D color and VVS or better clarity, and having Excellent polish, symmetry and overall Cut grades would get the Premium label. Diamonds not making the broader Standard grade (E-J color, at least VS clarity and VG in cut) would not be eligible for a Quality Assessment Report. “Using descriptive terms for the quality of laboratory-grown diamonds is appropriate as most fall into a very narrow range of color and clarity,” said Pritesh Patel, GIA president and CEO. “Because of that, GIA will no longer use the nomenclature created for natural diamonds to describe what is a manufactured product.”

Shortly after GIA made this announcement, HRD announced that they would no longer issue any grading reports for lab grown diamonds. The era of treating synthetic diamonds on equal footing with natural diamonds appears to be drawing to a close.

In late 2019 an outbreak of a highly contagious viral respiratory disease emerged from China and rapidly spread around the world in what would be a global pandemic of enormous proportions. By early 2020 with no vaccine yet available for this virus, the US was moving into shut-down mode with people staying at home and avoiding public places. This had enormous impacts on businesses of all kinds including jewelry retail and manufacturing. From large factories in India’s diamond cutting centers to retail jewelry stores all across America, the diamond and jewelry business came to a virtual standstill for many long months. Only when a vaccine was finally released did the world start moving again and businesses slowly began to crawl out of a very deep hole.

As the world was just starting to emerge from the pandemic, Russia invaded Ukraine setting off new anxieties and destabilizing the global order. Part of the world’s response to this aggression was a series of economic sanctions which included restrictions on the importation of Russian diamonds. Considering that approximately a third of all high quality diamonds are mined in Russia, supply chains were severed almost overnight. Businesses were in scramble mode to acquire new sources to stay in business. The natural diamond business had taken another major hit.

At the end of 2021 GIA announced that it had acquired the intellectual property of AGS Laboratories including their light performance cut grading technology. AGSL would be ceasing diamond grading operations at the lab and converting the facility to a GIA R&D center focused on cut quality analysis. They also kept key members of the AGSL cut grading team on staff. Soon after the acquisition GIA began offering AGS Ideal addendum reports to qualifying diamonds that were sent in for grading. The submitter would have to request the additional report at the time of GIA grading. A link to the addendum report appears on the standard grading report. This development signaled that GIA intended to deploy the AGS light performance technology more broadly in the future. Fancy shape diamonds, which GIA does not currently issue cut grades for, would be the logical area of reporting enhancement. The fact that GIA implemented the AGS Ideal report so quickly, not only for round diamonds but for fancy shape diamonds as well, indicates that GIA intends to keep the very strict AGS grading structure intact.

The United States under Donald Trump at the beginning of his second term initiated a global trade war by unexpectedly raising the tariff rate for goods entering the US to rates not seen for a century. Targets of this tariff war included many of America’s biggest trade partners and closest allies. In some cases rates were irrationally raised to astronomical rates as punishment for perceived grievances. Rates were raised, then lowered, then in some cases raised again in a dizzying and chaotic frenzy that paralyzed businesses and destabilized the world economy. The long term effects of this trade policy remain to be seen. It has already proven costly for American businesses and has raised the cost of products for US consumers, the two entities paying the tariffs. It has made it difficult for businesses to plan efficiently and has disrupted supply chains further, particularly in a diamond industry still trying to recover from a pandemic Russian sanctions and loss of market share to synthetics. It has forced countries to look to markets other than the US to trade with and has already resulted in a number of trade agreements that exclude the US.

Diamond discoveries in South Africa near the end of the 19th century propelled the diamond industry into the modern era. DeBeers snapped up mining claims in the early years and became a behemoth, at one time controlling a large majority of the global supply rough diamonds. They were also instrumental on the demand side putting enormous resources into promoting diamonds to the consumer market. Their long running “A Diamond is Forever” advertising campaign started just after WWII is credited for essentially creating the engagement and wedding ring market for diamonds.

The massive sway DeBeers enjoyed over the diamond market led them to run afoul of anti-trust laws, and to public relations problems that spawned any number of conspiracy theories and which persists today, despite the fact that DeBeers influence has been significantly reduced over the last several decades. New diamond discoveries in places like Russia, Brazil, Australia and Canada introduced very significant competition for rough diamond supply. DeBeers today suffers from many of the headwinds confronting the entire industry, and their ability to devote resources to marketing and to driving demand has likewise become severely constrained. This is a problem for the whole industry which has always depended on DeBeers to support consumer demand, especially in an era of major competition from synthetic diamonds. The creation of the Natural Diamond Council is a response to this new need. It remains to be seen how successful they will be in confronting the competition in the age of changing consumer demographics.

In the early 1970’s a young diamond broker in New York named Martin Rapaport began compiling detailed records of asking prices and selling prices of diamonds as he went from dealer to dealer showing his loose diamonds. He continued this practice as the dealers he visited showed interest in what other dealers were asking and paying. Ultimately this work took on a life of its own, ultimately becoming a pricing structure relied upon by the diamond world globally. The “rap list” is a trade publication that shows high asking prices for diamonds by size, shape, color and clarity. Round diamond prices are updated weekly, presumably based on actual data, while fancy cut diamonds are based on the Pear Shape list updated monthly. The enormous influence of the rap list for diamond traders has prompted questions about whether the dog is wagging the tail or the tail is wagging the dog!

The 4Cs stand for Cut, Color, Clarity, and Carat weight. Introduced by the Gemological Institute of America in the 1950s, they created a shared global language for evaluating diamonds.

Before the 4Cs, buying a diamond meant relying almost entirely on a jeweler’s opinion. After the 4Cs, consumers could compare diamonds across stores, cities, and eventually websites using standardized grading reports.

Cut controls light performance. It determines how much brilliance, fire, and scintillation a diamond returns to the eye.

A diamond can have excellent color and clarity, but if proportions are off, it can look dull. That is why the development of cut grading systems, first parametric and later performance based using ray tracing, became such a pivotal shift in the modern era.

GIA introduced a round brilliant cut grade in 2005 based on proportion ranges and modeling.

AGS Laboratories went further by developing a light performance based system using ray tracing to evaluate how light actually behaves inside a diamond. In 2022, GIA acquired AGS light performance technology and began integrating elements of that system into its own services.

The industry is still evolving in this area, especially for fancy shapes.

The 60/60 cut refers to diamonds with roughly 60 percent table and 60 percent total depth.

For years, this became shorthand for a well cut diamond. The problem is that many different proportion combinations can produce 60/60 numbers. Some are beautiful. Others are not. Modern light performance analysis revealed the limits of relying on two numbers alone.

Conflict diamonds, sometimes called blood diamonds, are stones seized by militants and sold to finance armed conflict against governments.

The Kimberley Process was created to address the problem of these diamonds entering the legitimate market. While it has reduced the problem significantly, vigilance is still required to eliminate the problem entirely.

Lab grown diamonds introduced large scale supply into what was historically a supply constrained natural resource market.

As production scaled and prices dropped, consumers were suddenly able to buy larger or higher color and clarity diamonds for less money. This forced natural diamond pricing, marketing, and grading institutions to adapt.

In 2024, GIA announced it would stop using the traditional 4Cs grading format for laboratory grown diamonds and instead issue a Quality Assessment Report using broader categories such as Premium and Standard.

The reasoning was that most lab grown diamonds fall within a narrow band of high color and clarity, making fine distinction less meaningful from their perspective.

This marked a major philosophical shift in how natural and manufactured diamonds are positioned relative to each other.

Yes. Especially in cut grading for fancy shapes.

With light performance technology now in the hands of major laboratories, the next frontier is consistent, performance based grading across all shapes, not just round brilliants.

The story is not finished.