The Legendary Argyle Mine

Argyle Diamond Mine Processing Plant, Photo Courtesy: Rio Tinto. Argyle Pink Diamond, Photo Courtesy: LJ West Diamonds.

Deep in the wilderness, in the east Kimberley region of Western Australia, the Aboriginal people pass down their history through oral storytelling. One of the stories, Barramundi Dreaming, is a mystical tale of how pink diamonds from the Argyle Diamond Mine got their color. According to folklore, three women were casting nets in the water to catch fish. In an effort to escape the nets, a barramundi fish jumped in the air and flew over the nets. In the process the fish dropped its scales in the water and on the rocks, which the legend says, turned into pink diamonds.

The Argyle diamond mine sits on land that belongs to the Miriuwong, Gidja, Malgnin and Wularr people who are the traditional custodians of this remote area. Diamonds were discovered in the region in 1979 and mining company Rio Tinto began operations at the Argyle Mine in 1983, leasing the land from its owners. The Argyle Pink Diamond Facility is located in Perth, Australia.

Surprise Discovery

During its 37-year lifespan, the mine produced some 865 million carats of rough diamonds. Most of the gems were lower quality brown or industrial diamonds. Then something unexpected and magical happened: Pink diamonds were discovered during production and through its lifespan the mine produced a steady supply of these gems in an extremely limited quantity. About one tenth of one percent of all of the diamonds found in the mine, were pink. Rarer still were red diamonds and even more rare – violet diamonds.

To put that in perspective, each year only about 50 to 60 pink diamonds were found in sizes above a half carat. Pink diamonds from the Argyle mine tend to range in size from 1 to 2-carats, with the very occasional gem reaching 3-carats. According to the miner, the gems are so rare that an entire year’s production of pink diamonds 1-carat and over would fit in the palm of your hand and it would take 15 years to collect enough pink diamonds to fill a champagne flute. Despite these strikingly small numbers, the Argyle mine produced 90 to 95 percent of the world’s pink diamonds. The remainder are found sporadically in Africa, Brazil and India.

Powerful Color

One of the attributes that sets Argyle pink diamonds apart from other pinks is their vibrant color. While they may be small, they have a powerful pop of color that ranges from soft powder puff pinks to vibrant fuchsias and magentas. According to the Gemological Institute of America (GIA), pink diamonds get their color from a distortion in the crystal structure of the gem as it is forming possibly due to the intense heat and pressure of being forced to the earth’s surface. The shift in the crystal structure causes the diamond to reflect light differently resulting in the pink colors that we see.

The rough stones were cut in the Argyle Perth facility by highly-skilled master cutters who carefully cajoled the best color and most sparkle out of each gem. The internal structure of pink diamonds makes them more challenging to cut and the artisans who worked on those stones had to be patient. Due to their internal structure it takes about four times longer to cut one of these precious pinks than it does a white diamond. From the time the diamond is found until the polishing is finished takes over a year.

Pink Diamond Tender

Once the diamonds were ready to sell, the stones were collected into a tender that travelled to major cities in the world to be viewed by about 150 dealers, retailers and collectors at invitation only events. The stones were sold by sealed bid and Rio Tinto never revealed the prices paid. What we do know is that pink diamonds can easily sell for $1 million to $2 million per carat and we could see prices take a leap in the next few years. In November 2020, the Argyle mine ceased production and with its closure the world has lost its one source that provided a steady supply of pink diamonds.

Rio Tinto has helped its Argyle employees make career transitions and it is working with the Traditional Owners and local stakeholders to dismantle the mine and rehabilitate the land, a process that is expected to take about five years. Once it is complete the land will be returned to the Traditional Owners as the custodians of Country to use for cattle grazing, tourism, cultural use and possibly small-scale agriculture.

Authored by Amber Michelle

The Allure of Vintage Diamonds

Bracelet Features Three Old European Cut Diamonds, Photo Courtesy: Global Gems

A mix of art and math, diamond cutting is a specialized skill that takes a rough rock from the ground and turns it into a dazzling object of desire. Through hundreds of years diamond cutting has evolved and changed as hand tools gave way to new technological innovations. The first diamonds were cut using hand tools and the cutter had to rely on his artistic ability and skill to cut the gems. This resulted in each diamond being slightly different with its own unique charm and personality.

Not to be confused with shape, cut is the arrangement of facets on a stone, while shape is its geometric form. Cut is very important to the appearance of a diamond. How facets are placed on a diamond impacts how much it will sparkle.

Early Diamond Cuts

Some of the first diamonds discovered in jewelry date back to the Roman era. These diamonds were in their natural rough state. Many years later the Table Cut was created and is widely considered to be the first diamond cut ever developed. The Table Cut took a rough diamond and cut off the tip of the stone, leaving a large, flat table-like area.

During the Renaissance period in the 1500s and 1600s some important diamond deposits were found in Brazil and India. Many of these diamonds made their way to Europe where skilled artisans began experimenting with ways to bring out the best attributes of these coveted gems.

These artistic experiments eventually led to the creation of the Rose Cut diamond. Developed in the 1500s, the cut got its name because it looks like a blossoming rose bud.  A Rose Cut diamond is dome shaped with a flat bottom. The dome is covered with triangular facets. Rose Cut diamonds have a lovely shimmering sparkle and a romantic, dreamy feeling.

Old Mine Cut Diamonds

While there were some intermediary steps that created new diamond cuts – such as the Mazarin that had 33 facets, the next cut to make a big impact in the diamond world was the Old Mine Cut, which first came on the scene in the 1700s. These diamond cuts follow the octahedral shape of the rough stone. Because each rough diamond is slightly different in form, Old Mine Cut diamonds can be found in round, square, cushion or rectangular shapes. They have 58 facets and are distinguished by a high crown – the top half of the diamond; small table, which is the large facet on top of the diamond and an open culet.  

When we look at a modern diamond, we are used to seeing the culet come to a point at the bottom of the stone. In an Old Mine Cut, there is no point at the bottom, instead there is a flat, open area. Since they were cut by hand, Old Mine diamond facet sizes and shapes will vary not only between stones, but also on the same stone itself.

Many Old Mine Cut diamonds were created before the advent of electricity. These diamonds were cut to be seen in candlelight and they are at their sparkling best when they are seen in that type of light, which is why they are sometimes called “candlelight diamonds”.  During the Georgian and Victorian eras, Old Mine Cut diamonds were at the height of their popularity.

Old European Cut

During the late 1800’s there was a new development in diamond faceting that led to the Old European Cut. Despite the name Old European, the cut was actually created in the United States by  business partners Henry Morse and Charles Field who established the first diamond cutting factory in the country. The diamonds were called Old European, because they were cut by people who had come to the United States from Europe.

The duo took cut parameters in a new direction focusing on smaller culets, better symmetry and smaller tables. This diamond cut became known as the Old European Cut and was much rounder in shape than its predecessor the Old Mine Cut. It also has a much smaller culet. Widely considered to be the precursor to the modern-day brilliant cut, the Old European Cut was popular in the first half of the 1900s.

Marcel Tolkowsky and the Ideal Cut

Enter mathematician and gemologist Marcel Tolkowsky. In 1919, Tolkowksy, who was working on his PhD at the University of London, did much of his research on “grinding” diamonds. His book, Diamond Design, grew out of his research and explained the best way to cut a diamond for maximum light return that creates the best sparkle, fire and brilliance. What he discovered is what we now know as the Ideal Cut. His research revealed that to coax out the best sparkle in the stone, a rough diamond needs to be cut into 58 perfectly proportioned facets. He also discovered that a diamond that was cut too deep or too shallow would lose light making it less sparkly. To this day, Tolkowsky’s Ideal Cut diamond is one of the most important modern diamond cuts.

As technology advanced and diamond cutting became more precise, diamonds began to have crisper facets and more defined lines and shapes. Yet despite these perfectly cut stones, vintage cut diamonds continue to capture the hearts and imagination of jewelry connoisseurs everywhere who love the handmade artisan feeling of these special treasures.

Authored by Amber Michelle

July Birthstone: Ruby

Above: Art Deco platinum, carved ruby and diamond bracelet, courtesy of Paul Fisher, Inc.

Celebrated present-day as the July birthstone, rubies have unceasingly enchanted and entranced humankind. From Greek mythology to Burmese tradition, the scarlet stone has served as a symbol for various societies, cultures, religions, and philosophies. Aptly referred to as the “King of Gems” in Sanskrit, rubies continue to be one of the most precious and coveted gemstones.

Ruby and sapphire are a variety of the mineral corundum, a crystalline form of aluminum oxide. Corundum is a 9 on the Mohs scale of mineral hardness, second only to diamond, making it a highly popular and wearable gemstone.

Ruby’s iconic red pigment comes from the presence of chromium in the compound: the higher the chromium concentrations, the stronger the red hue. Chromium can also cause fluorescence, which further increases the red color intensity. Rubies of the most saturated color, coupled with natural fluorescence, are referred to as “pigeon blood”. Untreated, gem-quality rubies with vibrant shades of red are especially rare and highly sought-after, asserting higher per-carat prices in the colored stone market.

The inimitable geology of Central Asia, Southeast Asia, and Mozambique are all sources for exceptional ruby crystals. For centuries, deposits in Burma (now Myanmar), especially those from Mogok in Northern Myanmar, produced incredible specimens of rubies, some with extraordinary “pigeon blood” vibrancy. In the late 2000s, gem-quality rubies were discovered in Mozambique, and the country has since become the world’s largest ruby producer. 

From armor augmentations to lavish ornamentation, craftsmen have employed the “King of Gems” for centuries, particularly as a mineral of choice for jewelry. Rubies have graced countless jewels through the various eras and design periods and continue to play an important role in the modern-day colored stone and jewelry fabrication markets.

Van Cleef & Arpels, platinum, ruby and diamond “margueritte” flower brooch, courtesy of J.&S.S. DeYoung, Inc.
Cartier 18K Gold and Ruby Clips, courtesy of G. Torroni S.A.

References

Giuliani, G. & Groat, L. (2019, Winter). Geology of corundum and emerald gem deposits. Gems & Gemology, 55(4), 464-489. GIA. https://www.gia.edu/doc/WN19-geology-of-corundum-and-emerald-gem-deposits.pdf

July Birthstone. GIA. https://www.gia.edu/birthstones/july-birthstones

May, L. (2016, November 23). 5 minutes with… A Burmese pigeon’s blood ruby ring. Christie’shttps://www.christies.com/features/5-minutes-with-A-Burmese-pigeons-blood-ruby-ring-7917-1.aspx

Rees, L. (2020, August 21). See the world’s rarest and most famous rubies. Galerie Magazinehttps://www.galeriemagazine.com/rubies-most-famous/

Ruby. SSEF. https://www.ssef.ch/ruby/

Ruby Care and Cleaning Guide. GIA. https://www.gia.edu/ruby-care-cleaning

Ruby Description. GIA. https://www.gia.edu/ruby-description

Ruby Quality Factors. GIA. https://www.gia.edu/ruby-quality-factor

Shor, R. & Weldon, R. (2009, Winter). Ruby and sapphire production and distribution: A quarter century of change. Gems & Gemology, 45(4), 236-259. GIA. https://www.gia.edu/doc/Ruby-and-Sapphire-Production-and-Distribution.pdf

Young, K. (2019, February 10). Rock stars: Diamonds may be a girl’s best friend, but blood-red rubies are a cut above other gemstones. CBS News. https://www.cbsnews.com/news/rubies-the-real-rock-stars/