Scientific guide about black diamonds

Nadezhda Iushkina

Scientific guide about black diamonds

Introduction

Diamonds are known for their high hardness combined with visual and aesthetic characteristics. The hardness of a diamond is determined by its crystalline structure, in which each carbon atom is bonded to other carbon atoms. This makes diamond an incredibly strong and hard material, allowing it to be used in various fields, including jewelry, industrial applications, and new technologies.

Black diamonds come in different shades: besides jet black, they can be shades of dark cognac, graphite, or asphalt colors.

The emergence of black diamonds is caused by several reasons: partial changes in the crystalline structure, in opaque black diamonds there is a high content of micro particles of graphite and amorphous carbon, invisible even under high magnification, in transparent black diamonds – a higher concentration of nitrogen ions. The bluish-black tint is given by a specific mineral – magnetite, which also has magnetic properties.

Research into the cause of color in black diamonds is relatively recent. Today we know that most naturally colored black diamonds get their color from large quantities or clouds of minute mineral inclusions such as graphite, pyrite or hematite that extend throughout the stone.

Black diamonds reflect light only through their facets. Many black diamonds have a distinct sparkle.

Another characteristic of some varieties of black diamonds is their matte opacity, which is just as mesmerizing as the sparkle and shine of the facets of other diamonds.

Black diamonds, with their captivating allure and mysterious origins, have been sought after by miners and gem enthusiasts for centuries. The history of black diamond mining spans various regions of the world, each with its own tale of discovery, challenges, and triumphs.

One of the most renowned regions for black diamond mining is Brazil, where these enigmatic gems were first discovered in the early 18th century. The vast alluvial deposits of the Bahia and Minas Gerais regions yielded an abundance of black diamonds, attracting prospectors from far and wide. However, the rugged terrain and dense vegetation posed significant challenges to miners, requiring perseverance and ingenuity to extract the precious stones from the earth.

In Africa, the Central African Republic emerged as a prominent hub for black diamond mining, particularly in the famous deposits of the diamond-rich regions. Here, miners navigate through dense forests and navigate treacherous rivers to reach the diamond-bearing gravels, where black diamonds are often found alongside other gemstones and minerals. Despite the remote and challenging conditions, the allure of striking it rich lures miners to these untamed landscapes in search of black diamond treasures.

In addition to Brazil and Africa, black diamonds have also been unearthed in other parts of the world, including USA and Russia. In Australia, the Ellendale Diamond Mine gained recognition for its production of high-quality black diamonds, adding to the global supply of these rare gems.

Despite the allure of black diamonds, mining them presents a myriad of challenges for miners. The remote locations of many black diamond deposits require extensive logistical planning and infrastructure development to access, often involving long journeys through rugged terrain and harsh climates. Furthermore, the geological complexity of black diamond formations poses technical challenges during extraction, necessitating specialized equipment and expertise to recover the gems safely and efficiently.

Moreover, environmental and social considerations play a crucial role in black diamond mining operations, with efforts to minimize ecological impact and ensure the well-being of local communities. Sustainable mining practices and community engagement initiatives are increasingly being prioritized to mitigate the negative effects of mining activities and promote responsible resource management.

Next, you will learn more about each type of black diamonds, their origin, composition, structure, human applications, and in the following chapter, you will be able to read about the largest natural specimens of black diamonds ever found and cut into beautiful jewelry settings. You will find it interesting to read about their history and unique characteristics.

The largest black diamonds in history

Nowadays, good quality and large black diamonds are rare and highly valued. In the past, black diamonds were not considered precious gems, and they could be bought for 5-10 dollars per carat. Now they can cost more than colorless or colored diamonds with equal weight characteristics.

Let's take a closer look at some of the most famous black diamonds, starting with the largest one.

Enigma

We'll start with the unique black diamond called "Enigma" with a record weight of 555.55 carats. At a Sotheby’s auction in February 2022, it was sold for over 4.2 million dollars. Despite its intricate and non-classical cut, the "Enigma" diamond has 55 facets. There is an opinion that it formed as a result of a meteorite impact. The owner of the diamond acquired it in its rough form in 1999. At that time, the stone weighed over 800 carats, and its processing took several years. Sotheby's adds that this is the largest fancy natural black diamond in the world. In 2006, it entered the Guinness World Records as the largest cut diamond in the world.

The Spirit of de Grisogono

Continuing our list of the largest black diamonds in history is The Spirit of de Grisogono, cut from 587 carats. It is the largest cut black diamond in the world, ranking 5th among the largest diamonds in the world.

The Spirit of de Grisogono was mined in the western part of Central Africa. To this day, none of the black diamonds can compare to the Spirit of de Grisogono in terms of purity and beauty. It was acquired by the Swiss jeweler Fawaz Gruosi, who was involved in cutting three out of the five famous black diamonds. He transported the crystal to Switzerland and cut the black diamond Spirit of de Grisogono to 312.24 carats in the form of a rose with a modern twist. This ancient cut, developed in India and known since ancient times, can be seen in other famous historical diamonds. Currently, the Spirit of de Grisogono diamond is set in the highest quality white gold and surrounded by 702 small white diamonds with a total weight of 36.69 carats. For over a year, Fawaz Gruosi studied the black diamond Spirit of de Grisogono before giving it this magnificent form, complementing the ancient rose cut with a modern design style. The black diamond Spirit of de Grisogono is described in the scientific work of the Gem Gubelin laboratory as a rare diamond specimen considering its color, quality, and large size. It has been in several private collections, but the jewelry company De Grisogono still owns the ring with the Spirit of de Grisogono diamond.

Gruosi

The black diamond called Gruosi was found in India in 1998. The Black Diamond Gruosi initially weighed 300.12 carats. Almost immediately after its discovery, this rare black crystal was bought by Fawaz Gruosi. The famous jeweler and watchmaker of the de Grisogono house had been studying black diamonds for many years. Cutting the black diamond into the Gruosi diamond proved to be difficult. Working with black diamonds requires skill and caution, as they are fragile in some areas and excessively hard in others. The cutting of this black diamond Gruosi was carried out in the Belgian city of Antwerp and took a whole three years. It was decided to give the black diamond Gruosi the shape of a heart. As a result of the processing, the Gruosi diamond lost more than half of its initial weight and turned into a black diamond Gruosi weighing 115.34 carats. Today, the black diamond Gruosi is set in a necklace of white gold and is accompanied by small black diamonds with a total weight of 58.77 carats, small white diamonds with a total weight of 378 carats, as well as garnets weighing 14.10 carats.

Prince of Johannesburg

The Diamond Prince of Johannesburg weighs 101.99 carats. The history of the black diamond Prince of Johannesburg remained unknown until the Amsterdam exhibition in February 1973, where it was presented. The stone is set as a pendant in the center of a diamond necklace.

Its owner is the jewelry house Louis XV, whose salon-store exhibited the necklace with the black diamond Prince of Johannesburg throughout 2007, then announced its sale, and experts estimated this decoration at $5 million.

Korloff Noir

Next, let's consider the black diamond Korloff Noir from the Korloff brand, founded in 1978 by Daniel Paillasseur – a gesture acknowledging the value and beauty of one of the most exquisite gemstones in the world, the black diamond Korloff Noir weighing 88 carats, cut from a 200-carat stone. Daniel acquired the famous black diamond in 1978. Before the revolution, it belonged to the Russian aristocrats Karlov-Sapozhnikovs. It was a kind of talisman passed down from generation to generation. In 1917, the family emigrated, and in the 1940s, the stone appeared on the European market. The diamond began to change owners, and once it ended up with the French jeweler – Daniel Paillasseur, who was genuinely in love with precious stones and had a passion for Russian history. Therefore, when it came time to name the company, he decided to name it the House of Korloff, as a tribute to the Russian roots of the magical diamond. Currently, the Korloff Noir is on display in one of the showcases of the flagship Korloff boutique in Paris.

Black Orlov

Next, we mention the Black Orlov diamond weighing 67.50 carats. It was cut from a 195-carat black diamond. New York jeweler Harry Winston exhibited the rare diamond to the public in its natural form for some time, and later adorned a platinum necklace with it alongside other diamonds. In 1990, 1995, and 2006, the stone was put up for sale at Sotheby's auction house. In 1951, it was presented at an exhibition at the New York Museum of Natural History, in 1964 – at a jewelry exhibition in Dallas, in 1967 – at the diamond pavilion in Johannesburg, South Africa, and in 2005 – at the London Museum of Natural History. In the early 2000s, the stone sparkled on the necks of actresses Felicity Huffman and Nicollette Sheridan, as well as on the neck of diamond book author Vicky Peterson.

Le Grand Noir Diamond

The Le Grand Noir Diamond weighs 56.65 carats. The history of the precious crystal "Big Black Diamond" was unknown until it came into the possession of the Louis XV jewelry house. The black diamond Le Grand Noir is set in the center of a pendant with diamonds. Experienced experts estimate this decoration at $755,000.

Amsterdam

And completing our list is the famous stone – the Black Amsterdam Diamond. It weighs 55.85 carats. In the early 1970s, the Black Amsterdam diamond was found in South Africa and ended up in a pile of stones deemed unsuitable for jewelry processing. A worker responsible for crushing such diamonds into dust for technological purposes noticed the sparkle and hardness of the black crystal. He set aside this black diamond and later showed it to his supervisor, thus presenting the world with this unique specimen. Expert analysis revealed a high-quality black diamond suitable for jewelry. In 1972, the future Amsterdam Black Diamond was acquired by the jewelry firm D. Drukker & Zn. The name "Black Amsterdam Diamond" was given in honor of the 700th anniversary of the Dutch capital, Amsterdam. This city was one of the first European centers of the diamond industry from the 17th century until World War II, after which diamond processing leadership shifted to Antwerp. The Black Amsterdam diamond first appeared for sale in Amsterdam in 1973 – it was presented in the showcase of the D. Drukker & Zn jewelry store. The Black Amsterdam diamond was cut into a pear shape weighing 33.74 carats. Typically, pear-shaped diamonds have 57 or 58 facets – the Black Amsterdam diamond has twice as many facets. As a result, despite its opacity, the Black Amsterdam Diamond has a uniquely stunning sparkle.

The jewelry company D. Drukker & Zn developed a pendant for the Black Amsterdam diamond, which best highlighted all its beauty and sparkle. In the center was the Black Amsterdam diamond surrounded by 15 small colorless white diamonds in a cushion shape. The Black Amsterdam diamond gained worldwide fame thanks to numerous international exhibitions. Its value in 1991 was $2 million. On November 14, 2001, the Black Amsterdam diamond was removed from its setting for the Geneva auction at Christie's. It sold for $352,000 – a record price paid for a black diamond. On September 27, 2001, the Black Amsterdam diamond received a certificate from the Geneva company Gem Tech Lab, confirming its rare monocrystalline origin. According to experts, the color of the Amsterdam diamond is formed by patterns of graphite particles in its crystalline structure.

Of course, history knows of many more large black diamonds, but many of them disappeared during various historical events or information about them was classified or little known, so I didn't consider all of them, but tried to only cover the largest and most interesting ones.

Ordinary black diamonds

Black diamond is a fancy diamond of deep black color, retaining some transparency and a characteristic silky luster. Unlike other colored diamonds, which mainly derive their color from chemical impurities or defects in the substance's structure, such as nitrogen, hydrogen, and boron, raw black diamonds owe their color to the inclusion of graphite and its clustering throughout the diamond.

Type Ia black diamonds: This type of black diamonds contains a large number of inclusions that give them a dark or black color. Inclusions may include graphite, pyrrhotite, pyrope, and other inclusions that form during the crystallization of diamonds.

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