Colour, clarity, cut, and carat weight – collectively, the 4Cs of diamond quality define a stone’s quality characteristics and contribute to its value. However, there were not always standard terms used in the industry. Less than a century ago, merchants used different wording for describing the same feature until one man made a revolution in the 1940s.
The History of the 4Cs of Diamond Quality
We know that diamonds are graded for 4Cs, which represent their colour, clarity, cut, and carat weight. However, before the 1940s, there were no consistent terms defining diamond quality, and any description was completely subjective.
Starting from the 16th century, merchants used inconsistent terms to describe the four elements of a diamond. The colour was usually described as “tint” or “tincture” when referring to yellowish diamonds and “river” or “water” when referring to colourless stones. Clarity was expressed as “without flaws/imperfections” or “with flaws/imperfections,” and for cut quality, they used “made well” or “made poorly.” Carat was the only term used consistently from the 16th century to today; however, it was not equal to 200 milligrams or 0.2 grams until 1907.
In the early 20th century, Robert M. Shipley, a former retail jeweller in Wichita, Kansas, established the Gemological Institute of America (GIA) in 1931. The facility was dedicated to research and providing gemological education to aspiring jewellers. In 1934, he established another organization, the American Gem Society (AGS), whose members were GIA graduates.
To bring consistency and standardization to the diamond industry, Shipley standardized the diamond value terms we use today, calling them the 4Cs of diamond quality. These factors were easy to explain and remember, so they became part of the industry vocabulary. While it is not known exactly when Shipley began teaching the 4Cs, the term appears in newspaper articles as early as 1941.
The 4Cs and the Diamond Grading Scales
Shipley’s innovative ideas were well received by jewellers. However, Richard T. Liddicoat, who succeeded Shipley as president, along with his colleagues Lester Benson, Joseph Phillips, Robert Crowningshield, and Bert Krashes, took the concept of the 4Cs further.
Their efforts included not only the creation of the widely recognized GIA D-to-Z Color Scale and GIA Clarity Scale for diamonds but also the establishment of scientific techniques and protocols to accurately evaluate a diamond’s quality.
Before the introduction of the 4Cs and Liddicoat’s innovations, the diamond industry was plagued with confusing and inconsistent colour grading systems. Retailers used disparate methods with descriptors such as “A,” “AA,” and “AAA,” leading to significant variability in the way colour quality was communicated to consumers. Also, most diamond wholesalers utilized terms such as “rarest white” and “top Wesselton” in addition to the abovementioned grading systems. This lack of standardization made it hard to evaluate and compare diamonds accurately and reliably.
Since the 1930s, GIA had been developing a precise and impartial colour grading system for colourless to light yellow diamonds. The aim was to establish a grading system based on exact standards instead of ambiguous terms and comparative assessments. In 1953, Liddicoat introduced the GIA D-to-Z colour scale, where the letter “D” indicated the top grade (colourless) because of its unfavourable connotation, making it less prone to be misinterpreted or misapplied.
Richard T. Liddicoat and his colleagues also established the methods to be used for grading a diamond’s colour accurately and consistently. This included specifying the lighting conditions and neutral background against which a diamond should be evaluated, as well as developing sets of predetermined colour value “master stones” against which diamonds could be compared.
Today, the D-to-Z diamond colour grading system pioneered by Liddicoat and his colleagues is used worldwide, and the GIA laboratory adheres to strict colour grading procedures.
The grading of diamond clarity was another aspect of the industry that suffered from ambiguous language and inconsistent evaluation methods. Some professionals used terms such as “perfect” or “without flaws” and “with imperfections,” which were vague and lacked precision. Others employed familiar terms like VS and VVS but without universally accepted definitions.
Richard T. Liddicoat and Lester Benson incorporated these terms while developing a clarity-grading scale, but they also created well-defined categories and expanded the number of grades in each category to account for the diverse array of diamonds available. This scale was refined over the years, and today, the GIA Clarity Scale includes six distinct categories spanning from Flawless to Included, and it consists of eleven specific grades.
The advancement of gemological microscopes as a tool for evaluating clarity was another significant innovation of GIA. GIA graders use this tool to plot the inclusions and blemishes in diamonds, for which a full GIA Diamond Grading Report has been requested. This high degree of precision in clarity grading made possible by these innovations has significantly improved the accuracy and consistency of diamond grading.
Liddicoat and his colleagues recognized the importance of a diamond’s Cut, which describes how well a diamond interacts with light. Liddicoat sought the expertise of Belgian mathematician and diamond cutter Marcel Tolkowsky to determine “ideal” proportions for a round brilliant cut diamond and introduced a rating system that included deductions for proportions that deviated from those standards.
Over time, GIA’s system for evaluating Cut has evolved. In 2006, after extensive research incorporating advanced computer modelling and observational studies, GIA introduced the GIA Cut Grading System for round brilliant cut diamonds. The GIA Cut Scale, ranging from Excellent to Poor, now describes how effectively a diamond interacts with light, resulting in the brightness, fire, and scintillation that are synonymous with a high-quality round brilliant diamond.
How Advertising Affected the 4Cs
In the early 1940s, the Gemological Institute of America partnered with De Beers to generate interest in diamonds and educate the public. This collaboration led to the adoption of the term 4Cs by jewellers in articles and communications with their clients.
Within a couple of years, Robert M. Shipley enlisted Gladys Babson-Hannaford, a lecturer from N. W. Ayer & Son, an advertising agency founded in 1869, to travel across the United States and educate jewellers on the 4Cs and how to communicate them to their buyers.
In 1954, N. W. Ayer & Son wrote an article for JCK magazine titled “Secrets of the Diamond Expert,” which focused on the 4Cs and was intended as a speech for jewellers to use when addressing consumer groups. However, it wasn’t until August 1962 that the term 4Cs of diamond quality became popular among both jewellers and consumers.
Interestingly, De Beers, who had been involved in GIA advertising campaigns, did not adopt the term 4Cs until it became widely accepted.
Today, the 4Cs are universally recognized as the four main quality characteristics of a faceted diamond, used by both merchants and consumers when selling and buying diamonds.
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