Diamond design – A little history

Throughout history, the concept behind diamond cutting was to shape and facet them for their subjective beauty based on the optical knowledge of the different era’s. Diamonds were mainly purchased and collected by royalty and their courtesans as they were unreachable and in some cases unlawful to be possessed by the common people.

Diamonds were a scarce resource, found mostly in river beds in India and Brazil whose high value was justified by the fact that only a few kilos/pounds of rough diamonds were produced each year.

The diamond cutting industry was controlled by a small number of families who jealously guarded their craft secrets. Diamonds were planned and cut to fulfil the desires as expressed by their patrons.

That all changed with the formation of De Beers, the South African diamond discoveries and what the industrial revolution contributed all at around the second half of the 19th century.

Since about that time, rough diamonds have been mined and produced in abundance forcing the mass production and marketing of diamonds which evolved through the 20th century up until present day.

Louis XIV and the French Blue(Hope) Diamond

20th century evolvement – a quick view

1900’s– The manual saw is adapted by the general industry implementing even more diamond production. Small diamonds are starting to be cut in masses.

1900’s– Industrial revolution makes mass production possible starting a race for lower costs, speed and quantities. Diamond cutting assembly-line methods and models are implemented in Amsterdam, Antwerp, USA and Israel.

1919– Tolkowsky publishes his “Diamond Design” thesis for round brilliants which also manages to transmit into fancy shaped brilliant designs.

1931– GIA Laboratory is founded and standards are starting to be developed.

1938– De Beers implements heavy marketing by hiring Philadelphia ad agency N.W. Ayer who manages to change the landscape the way diamonds were conceived by people who thought diamonds were just for the ultra wealthy.

1947– Frances Gerety who is employed by N.W. Ayer comes up with what is considered the slogan of the 20th century “A Diamond Is Forever”.

1955– GIA issues its first grading report which becomes a universally accepted benchmark for jewelry industry.

1978– Martin Rapaport creates the “Rapaport Price List” which has become the standard baseline for pricing wholesale polished diamonds worldwide until present day.

1980’s– The first hearts & arrows round brilliants are marketed exclusively in Japan.

1988– Sarine is established and offers innovative non-contact measuring devices.

1996– AGSL introduces the first proportion based cut grade for round brilliants.

2005– AGSL introduces the next step in cut grading implementing a three dimensional ray tracing technology in order to measure light performance.
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2005– GIA introduces its cut grading system for round brilliants.
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Diamond Design by Marcel Tolkowsky

Cutting diamonds in the 20th century.

De Beers control of the supply & demand through most of the 20th century have had implications on how the diamond cutting industry developed during that time, prices were kept stable while inching up consistently throughout the years. Supply was also kept to a growth pattern consistent with the consumable appetite which was being developed by the western world.

The industrial revolution of the earlier years helped the diamond cutting industry develop tools and methods allowing the manufacturing of the new quantities of rough diamonds entering the pipeline. Big assembly type cutting (systems) factories were put in place, a round brilliant could have went through seven different cutters in order to be completed. Things were moving systematically fast!

Diamond saw introductions

Another major development in the early 20th century was the introduction of the diamond saw. The ability to saw a diamond into two or more diamonds made a huge impact on the value and the cut proportions of what we define as modern 20th century diamond cuts.

Until the introduction of the sawing methods and tools, diamonds were either cleaved (developing usually flat off-shapes) or cut & polished entirely on the wheel which resulted in one polished diamond per rough diamond.

Diamonds were cut to different proportion ratios prior to the saw invention usually exhibiting higher crown heights in relation to the pavilion depths and smaller tables thus enabling different shaped facet surfaces which handled light differently than the modern cuts developed after the introduction of the diamond saw.

The diamond saw is significantly responsible for the proportions cutters implement today on most of the diamond production world wide. Usually a flatter proportion set ratio which is derived from a low crown height in relation to pavilion depths.

Presently when a diamond nears its “allowed” total depth limits (62.7% round brilliants and 69.x% fancy shapes) all red lights start flashing as a caution! The reason being is that due to the nature of its “modern” proportions it is likely that the diamond was cut to preserve extra carat weight, the problem arises when the weight preservation is kept on the pavilion side which really limits the light return potential thus displaying a smaller diameter for its carat weight.

Diamond saw

Grading reports

During the second half of the 20th century, the cutting industry started to slowly be dependent on gemological grading reports, until the 1980’s grading reports were simple and assured that the diamonds consumers were purchasing were authentic and translated a certain value based on the four C’s.

Upon entering the last two of decades of the 20th century, grading reports started to implement heavier burdens on the cutting industry in general. Witnessing the popularity of the Hearts & Arrows designed diamonds in the 1980’s, Japan started a new academic challenge for diamond cut enthusiasts and grading laboratories. Three dimensional precision became an integral part of diamond cutting standards which at its height in 2005 both GIA & AGSL introduced their cut standards for round brilliants.

AGSL introduced their (second round) three dimensional ray tracing technology and GIA their cut grading system for round brilliants, both different grading methods for the same purpose, creating the ultimate round brilliant (circa 2005).

Unfortunately since then the large majority of the cutting industry has been playing the “numbers and papers game”, achieving the correct numbers and wordings on the grading reports became the ultimate priority. For round brilliants achieving the GIA triple X or AGSL Ideal triple 0 and for fancy shapes, an easier task by achieving GIA’s (double X) excellent polish and symmetry goals while staying within the current numbers norm.

Since 2005 there has been no urge to further develop diamond design, the world has become mute and/or comfortably numb to the available papered cut proportions. If it’s graded as such, it’s good enough!

AGS Platinum Light Performance Diamond Quality® Document

Rapaport Price List

Towards the end of the 70’s, Martin Rapaport created Rapaport Price List, a published platform which claimed to be a baseline for the pricing of wholesale diamonds, a list based on “Approximate High Cash Asking Price Indications”.

There was plenty controversial amongst diamantaires when the lists first originated. Today forty years later, the controversials did not disappear and the industry noise around the Rapaport price list is still heard around the world almost on a weekly basis.

What startles me presently is that if you hypothetically take away the Rapaport Price List from most diamantaires desks, they would probably not know how to value their own diamond stock for a simple inventory.

Throughout the years, I have been suggesting industry professionals must adopt a different value model for their diamond offerings. I believe we should go back to valuing our diamonds based on total selling price like a total price per stone or alternately total price per layout, pairs, sets etc. after all, jewels set with diamonds do not sell for “per carat” prices.

Three dimensional Precision round brilliants, the birth of H&A

1980’s came along and with it demand for a new type of round brilliant. Japanese consumers became all raged for extremely high level of craftsmanship when it came to choosing diamonds for their engagement rings.

Such diamonds needed to be cut to high three dimensional precision levels to satisfy a new tool which according to rumors was developed by a Japanese inventor for diamond optical symmetry evaluation. This tool came to be known as the Hearts & Arrows viewer, it was a rather simple red reflector device which displayed a three-dimensional view of the diamond when viewed through it.

Up until this time, cutters were mostly cutting to satisfy two dimensional symmetry designs. In order for cutters to successfully achieve the symmetry requirements for H&A diamonds, tightly controlled crown & pavilion facet slopes (angles) were not the only important factors anymore, exact *Azimuth angle, facet shapes and surface sizes became an integral part of the cutting process required for H&A diamond achievement.

At about the same time, a new technology was being introduced in Israel, the development of the non-contact laser measuring devices which enabled cutters to enter this new world of three dimensional optical symmetry cutting. It is no wonder that many of the H&A diamonds of those times were cut & polished in Israel.

*For more info

Three Dimensional Precision - Wire frame and ray-tracing image generated by DiamCalc

New Technology entering the diamond industry

Sarine Technologies (est. 1988) first developed non-contact measuring devices to accommodate the colored gem industry, that was the initial focus since the early stakeholders came from the colored gems business. After a few years of R&D, Sarine noticed that servicing the diamond industry can be much more rewarding as its a much larger industry and amended their technologies accordingly.

The technology for diamonds was developed to primary service round brilliant cuts which are based on a rather simple eightfold symmetry design which has less room for measuring errors thus creating a most efficient tool for the round brilliant.

Throughout the years Sarine and the few other companies which offer similar solutions made some advancements to service the fancy shaped world. But due to its extreme complexity and lack of general demand by cutters we are still far away from the precision measuring levels required for advanced fancy shape design.

Back to the round brilliant, today most cutters will utilize the technologies available to achieve and reach the desired laboratories top cut grading threshold. Once cutters reach the level which will allow this top grade, their job is completed with another near perfect diamond.

For fancy cut diamonds, cutters will aim to achieve what seems to be the top grading scale for fancy cut diamonds. In today’s market, it is perceived that by achieving both an excellent grade for polish & symmetry, the assumption is that such diamonds are at the top of their cut grade echelons when it comes to cut craftsmanship.

This is a misconception, the actual grading of fancy shaped diamonds does not include “a cut grade” as *its not available for fancy shaped diamonds in general.
Excellent polish & symmetry grades do not cover the three dimensional cut grade offered for the round brilliant. In a nutshell, excellent polish & symmetry grades don’t tell the tale of beauty. Such grades simply confirm excellent facet surface polish and meet point symmetry but don’t touch the subject of light performance and/or play-of-light such diamonds display.

*Some limited proprietary cuts are eligible for AGSL cut grades.

Sarine Technologies measuring device

Gemological grading reports, the path to better cut diamonds

As mentioned above, until the mid 1990’s grading reports were mostly to put consumers mind at ease as far as the 4C’s. From around 1996 when AGSL developed its proportion based cut grade, cutting diamonds changed gears and cutters for the first time were forced to cut to specific angular proportions set numbers which required a certain precision level to successfully achieve.

In 2005 GIA announced the addition of an overall cut grade to round brilliants which were proportion based on both science and human observation statistics (very similar to what AGSL offered already in 1996). That same year, AGSL announced that they were moving beyond proportions based cut grading and presented a new grading platform that revolves around the actual light performance measurements of the diamonds or what we call “ray-tracing technology”.

This again changed the game in the cutting industry which required cutters to delve deeper into three dimensional optical symmetry and complicated the process further in order to achieve the top AGSL cut grade of triple 0 or Ideal. These requirements added a burden which now required cutters to cut & polish the facets of a round brilliant to exact shapes, sizes, angles and azimuth slopes because each and every facet placement was crucial to its successful achievement.

From personal experience I can vouch this has been a heavy burden in general for cutters, no wonder the AGSL triple 0 threshold requires very accurate cutting techniques which were adopted by a minority of cutters. AGSL cut graded diamonds are considered a small specialized niche in the industry as GIA grading reports and their cut grades are still the dominant gemological grading institution.

Designing diamonds, what does this mean?

Diamond cutting was for centuries based on economical and preferable outcomes of rough diamond shapes and their irregularities with the concept of cutting the largest and heaviest polished diamond.

In the beginning rough diamonds were exploited to their fullest. Standard faceting designs were non-existent while cutters cut to eliminate external irregularities and internal inclusions as a primary objective and simultaneously adding facets to allow the diamond to glitter when light struck it.

Diamonds were worn mainly for nightly court affairs and balls where candle light would allow the mysterious sparkle of diamonds to be noticed and highly appreciated. One of the reasons old cut designs are regaining their popularity status is because their old-world faceting designs allow for larger more prominent flashes where the viewer can enjoy its blocky play-of-light in almost every lighting environment.

The 20th century changed this historical landscape, suddenly diamonds were abundant, the industrial revolution allowed for mass production and finally a faceting standard was born. This mass explosion evolved into what we have presently, an over abundance of round brilliants, some say over 80% of production and the additional 20% are maybe ten fancy shapes which have barely evolved over the last century of diamond cutting.

Mostly two faceting designs are implemented, the brilliant which originally developed for the round shape and the step-cut which actually originated for colored gems, more specifically the Beryl family of crystals but seem to work its wonders on diamond material and more specifically its natural octahedron shape. Naturally over the course of a hundred years some other hybrid (brilliant and step-cut type) designs were born but none made it to popular heights of demand.

Designing diamonds never became as meaningful as they are today (in the past, this term didn’t even exist). Current technologies allow us to virtually design and plan shapes and cuts before even touching a diamond and then viewing its realistic play-of-light results. This a huge change from R&D on the material itself, a standard practice for whoever wished to experiment only one or two decades ago, myself included.

Cutters today have the ability to educate themselves (for free) on the science of light and its behaviors within the diamond medium. This knowledge allows the full control for desired light paths and reflections. Planners are able to design reproducible play-of-lights to accommodate innovative shapes and faceting designs.

Who said diamonds must be cut to old-world optical preferences, why not add diamond sculptures or similar to the repertoire? Such certainly know how to handle light at least as good as common diamond cuts! A food for thought!

Future of Designing Diamonds - ETAS big sphere image generated by DiamCalc

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