In the depths of the planet, the most precious gems in the world, blue diamonds, are formed. These enigmatic stones have a complex geological description, as well as being very valuable and rare.
The National Museum of Natural History in Washington, DC exhibits the most famous example of the Hope Diamond, in a sophisticated and deep blue-gray. As shown in the following image:
Characteristic
Are blue diamonds because the color of his body is blue. Finding this gem naturally is difficult, generally the mineral inclusions it presents are scarce. These characteristics and its great clarity give it its high value.
Few mines in the world produce blue diamonds, and they do it in small quantities. The bluish coloration is due to small portions of boron, on the crystal lattice. This blue jewel can also be created artificially in laboratories, and with natural diamond treatments.
Why are they blue?
When a diamond has only carbon atoms in its structure, it will be considered pure, without defects, and will be colorless. When alterations occur in the crystal lattice, colored diamonds appear. Among the alterations that occur are the replacement of carbon atoms, and the presence of non-diamond mineral particles embedded in the diamond.
The blue coloration is often produced when a small amount of boron replaces carbon atoms in the crystal lattice. The occurrence of these events is paradoxical, since boron is rarely found in the remote environment of the Earth, where natural diamonds are generated.
A small concentration of boron is enough to generate the blue color of the diamond, as the concentration increases the blue color will be more intense.
Boron can enter the diamond lattice, due to its small size, and replace a carbon atom (as shown in the image). However, it has one fewer electron, in relation to carbon, this translates into a deficiency of electrons, causing alterations in the crystalline structure of the diamond.
This alteration affects the passage of light through the diamond. When light falls on the diamond, it causes it to absorb the red fraction, and transmit the blue fraction. When the transmitted light reaches the human eye, the blue diamond is observed.
Boron substitution in diamond: It happens that when boron atoms replace carbon atoms in the crystal lattice of the diamond, it causes the mineral to selectively absorb the red wavelengths of light and selectively transmit the blue color and therefore are the wavelengths blue those that reach the viewer.
How are they formed?
For many years geologists believed that diamonds found on the surface were created with elements from the Earth’s surface layer 100 to 150 kilometers away.
The finding of a group of researchers in 2018 was surprising, when obtaining a number of blue diamonds formed at pressures corresponding to a very deep layer of the Earth, approximately 410 to 660 kilometers. These also had inclusions, whose origin could only be from materials from the oceanic lining.
These discoveries clarified why the blue diamonds They are only found in small quantities in the mines. The location of those mines was on a slab of subducted oceanic crust, pushing boron into the depths.
Later, thanks to volcanic eruptions, the elements present at that depth rose to the earth’s surface.
Famous blue diamonds
Between the blue diamonds best known worldwide are:
Diamond Hope
The Hope Diamond, an ancient jewel dating from 1653. It belongs to the Smithsonian Institution, and is the main attraction of the gem exhibition. It is the most famous gemstone worldwide, valued between 200 and 250 million dollars. In the following photo you can see a replica of the Hope Diamond:
Diamond Wittelsbach
The historical value of the Wittelsbach diamond made it attractive to many, with its luxurious blue-gray coloration. Laurence Graff bought this gem and had its virtues improved, increasing its value, greater than 80 million dollars. A replica of this jewel can be seen in the image:
Okavango Blue Diamond
First unveiled in April 2019, the “Okavango Blue” a 20-carat diamond owned by the Botswana government.
Josephine’s Blue Moon
12 karat cushion shaped gemstone with Fancy Vivid blue tint. Sold during 2015 in a Sotheby’s sale in Hong Kong for $48.4 million.
How much do blue diamonds cost?
The most valuable diamonds are natural diamonds with an even distribution of pure blue color in the body of the gem. Being rare, their sale price can exceed a million dollars per carat. Below are the prices of some diamonds, according to recent auctions.
The blue diamonds natural, they are altered acquiring a green or gray secondary hue. Blue-green and blue-gray diamonds are rare, and like natural blue gems with a faint hue, they are sold for lower prices.
| Blue diamonds sold at auction | |||
|---|---|---|---|
| Name | Polished Carat Weight | Color | Price |
| Oppenheimer Blue | 14.62 | elegant vivid blue | $57,231,903 |
| josephine blue moon | 12.03 | elegant vivid blue | $48,468,158 |
| Memory of Autumn Leaves (Apollo) | 14.54 | elegant vivid blue | $42,087,302 |
| the diamond zoe | 9.75 | elegant vivid blue | $32,645,000 |
| De Beers Millennium Jewel 4 | 10.1 | elegant vivid blue | $32,013,223 |
| The blue | 13.22 | elegant vivid blue | $24,202,829 |
| The diamond blue sky | 8.01 | elegant vivid blue | $17,074,168 |
| Bvlgari blue | 10.95 | elegant vivid blue | $15,762,500 |
| the diamond there | 5.0 | elegant vivid blue | $13,873,082 |
| blue diamond ring | 13.39 | deluxe deep blue | $9,288,823 |
| The Farnese Blue | 6.16 | dark blue gray fantasy | $6,713,837 |
| blue diamond ring | 3.47 | deluxe deep blue | $6,663,300 |
| ring etc | 3.37 | deluxe deep blue | $2,770,856 |
| green-blue diamond ring | 1.11 | Fancy Vivid green-blue | $415,111 |
| blue and colored diamond ring | 2.11 | elegant vivid blue | $379,393 |
| teal pearl and diamond ring | 1.62 | Fancy Vivid Teal | $350,880 |
| blue diamond ring | 0.87 | elegant blue | $231,203 |
Lab-Made Blue Diamonds
Many people want to show off blue diamonds, which is why ways of treating them and producing the blue color have emerged. Irradiation, treatments with high temperatures and pressure, coating with colored material on the surface of the gem, are used with the aim of producing the blue color in the jewel.
Cultured diamonds are made by incorporating boron into the culture. These diamonds are quite common and are offered at lower prices, offering an equally attractive alternative for a public that cannot afford genuine diamonds.
Blue diamond producing mines
Few mines form blue diamonds, and the most famous have been discovered in three places:
- Mines in India. Located in Golconda Sultanate, India. The most famous jewels Hope Diamond and Diamon Wittelsbash-Graff were found in these mines. The table below shows a list of the blue diamonds from Golconda.
- South African mines. Known as the Culligan mine, the world’s most important diamond generator. Produces blue diamonds larger rough, and a valuable portion of heavyweight diamonds. It currently belongs to Petra Diamonds. The following table lists the blue diamonds most important of the Cullinan mine.
- Western Australian mines. The Argyle mine generates the largest volume of diamonds in the world. Although the production of blue diamonds is minimal, for 2009 they offered a collection of diamonds between blue and purple accumulated over several years.
| Major Blue Diamonds from Golconda, India | ||
|---|---|---|
| Name | Polished Carat Weight | Color |
| idol eye | 70.21 | elegant light blue |
| the diamond of hope | 45.52 | Dark Blue-Grey Fantasy |
| Mouawad Blue | 42.92 | elegant blue |
| Crown of Charlemagne | 37.05 | elegant light blue |
| sultan of morocco | 35.27 | whimsical blue-gray |
| Wittelsbach Graff | 31.06 | elegant deep blue |
| Brunswick Blue | 13.75 | elegant blue |
| Major blue diamonds from the Cullinan mine | ||
|---|---|---|
| Name | Polished Carat Weight | Color |
| the blue heart | 30.62 | elegant deep blue |
| blue lily | 30.06 | deluxe deep blue |
| the heart of eternity | 27.64 | elegant vivid blue |
| transvaal blue | 25.00 | elegant blue |
| Sam Abram Fancy Blue | 20.17 | elegant vivid blue |
| Graff Blue Ice Diamond | 20.02 | elegant deep blue |
| Oppenheimer’s Blue | 14.62 | elegant vivid blue |
| the blue empress | 2:00 p.m. | elegant blue |
| The Begum Blue | 13.78 | elegant deep blue |
| The blue | 13.22 | elegant vivid blue |
| blue magic | 12.02 | elegant vivid blue |