Full size / Above Type IIa rough diamond, which sold for $53 million, or $47,777 per carat, is the fourth-largest diamond ever found: "Following successful negotiation with Lucara Diamond Corp, Laurence Graff has acquired the world’s most valuable rough diamond – the Lesedi La Rona – weighing a record-breaking 1,109 carats. The deal was closed with a handshake after more than a year of negotiations. Unearthed at the Lucara Karowe mine in north-central Botswana, the hypnotic Lesedi La Rona is the largest gem quality rough diamond discovered in over 100 years. This magnificent stone has been identified by The Gemological Institute of America as possessing exceptional quality and transparency, earning the full significance of its name, which means ‘our light’ in Botswana’s Tswana language." (Source)
Every diamond is unique because of its imperfections. These lattice or optical defects are caused by trace elements and other impurities, causing distinctive color and clarity. The presence or absence of these defects, their amounts, and their arrangement within the lattice can affect a diamond’s appearance, sometimes in dramatic ways. As such, diamond lovers know by heart that the “Four Cs“ (carat, cut, clarity, and color) are commonly used to determine the value of a gem. The diamond type, however, is only rarely discussed, yet all the more important to serious diamond connoisseurs, collectors and investors alike – and that´s because almost all diamonds are Type I and only a tiny fraction of all mined diamonds is Type II. Among all diamonds, those that are Type IIa are chemically the most pure and as such (almost) perfect, causing the greatest astonishment and the highest prices.
Today, Arctic Star Exploration Corp. announced to have received the results of a diamond type study based on 12 diamonds with a diameter of >0.3 mm retrieved by caustic fusion analysis of the Sequoia Kimberlite in 2021 at is Diagras Property in Northwest Territories, Canada. The diamond laboratory at the Saskatchewan Research Council studied these diamonds using Fourier Transform Infrared ("FTIR") Spectrometry to determine the concentration and aggregation state of nitrogen within the diamonds.
The result shows that 50% of the analyzed stones are nitrogen-free Type IIa diamonds, which according to Arctic Star "adds to a number of lines of evidence [see here and here] that this kimberlite complex has the potential to carry >50ct gems, indicator mineral chemistry collaborates with this, along with the diamond size distribution and the diamond descriptions (all described as clear white)".
For example, Type II diamonds constituted 25% by weight of the diamonds in the AK-6 pipe at the Lucara Karowe Mine in Botswana, where the above pictured Lesedi La Rona diamond – among several other exceptionally large gems – have been recovered. (Source)
Below figure from today´s news-release shows how unusual it is to have found a kimberlite with such a high percentage of Type II diamonds:
Full size / Left: Diamond type distribution from Sequoia Kimberlite Caustic Fusion; Right: Estimated global distribution of these diamond types.
Arctic Star stated: "The results show that 50% of the diamonds are nitrogen free type IIa diamonds, 33% Type IaA, and 17% Type IaB. See Figure 1 showing a pie graph depicting the results. This is in contrast to the global distribution where it is estimated Type IaA dominates 96% and Type IIa diamonds only make up 2%."
In a video news-release published today, Buddy Doyle (VP Exploration at Arctic Star) explained the significance of today´s announcement:
Click above player or here to watch Arctic Star‘s VP of Exploration, Buddy Doyle, explain the significance of today‘s news.
According to Wikipedia: "Type Ia diamonds make up about 95% of all natural diamonds and contain up to 0.3% nitrogen impurities. Type IaA: Nitrogen atoms are in pairs; these do not affect the diamond´s color. Type IaB: Nitrogen atoms are in large even-numbered aggregates; these impart a yellow to brown tint. Type II diamonds have no measurable nitrogen impurities. The crystals as found tend to be large and irregular in shape. Type II diamonds were formed under extremely high pressure for longer time periods. Type IIa diamonds make up 1-2% of all natural diamonds (1.8% of gem diamonds). These diamonds are almost or entirely devoid of impurities, and consequently are usually colourless and have the highest thermal conductivity. Many famous large diamonds, like the Cullinan, Koh-i-Noor, and Lesedi La Rona, are Type IIa. Type IIb diamonds make up about 0.1% of all natural diamonds, making them one of the rarest natural diamonds and very valuable. In addition to having very low levels of nitrogen impurities comparable to Type IIa diamonds, Type IIb diamonds contain significant boron impurities [giving such diamonds a distinct blue color].“
Full size / "Diamonds are rare, which gives them a high value at a low volume. They are precious, mysterious, magical, and exceptionally beautiful. The more the worlds diamond supply is depleted, the more the value increases. Investment diamonds are considered a haven because they increase in value throughout the years, but only quality diamonds stand out." (Source)
According to Leibish: "To sum things up about various types of diamonds: Type I diamonds are the most common. They represent 98% of all natural diamonds and have detectable traces of Nitrogen. Type Ia stones contain clusters of Nitrogen atoms throughout the crystal structure of the stone. They tend to emmit a yellowish tone. Type Ib diamonds contain Nitrogen atoms as well. Only, they are all singular as opposed to clustered groups. These stones are 0.1% of all diamonds and emit a strong yellow, orange, brown and even green color tone. Type IIa diamonds are the most valued and collectable items. They contain either very little or no Nitrogen atoms in the crystal structure of the stones. White stones are exceptionally colorless and Fancy Colored diamonds are often found with a brown, purple, or pink tone. They represent only 1% - 2% of all diamonds. Type IIb diamonds contain elements of Boron within the structure. As a result, they often emit a blue or gray tone. They represent only 0.1% of diamonds. In short, Type IIa and Type IIb stones are the most unique and collectable items. Although, especially in the case of fancy colored diamonds, since no stones are exactly alike it is important to assess each diamond on its own. One should never assume that a diamond will be perfect because it is graded a specific class or that it is worthless because it is of the more common type stones."
According to Ritani (2022): "Type IIa diamonds have no measurable nitrogen or boron impurities. They are the most chemically pure diamonds and have the highest thermal conductivity. Type IIa diamonds are often colorless or near-colorless. They can also be gray, light brown, light yellow, or light pink. Natural Type IIa are extremely rare – only 1-2% of earth-grown diamonds are Type IIa. However, most lab-grown diamonds are Type IIa. When diamonds are tested in a lab, a major indicator that they are lab-grown is when they test as a Type IIa diamond because they are so rare in nature. Earth-grown Type IIa diamonds are incredibly valuable because they are so rare. These natural diamonds are well known for their beauty and their large carat weights. The Elizabeth Taylor Diamond, also known as the Krupp Diamond, is a Type IIa Asscher cut diamond weighing 33.19 carats. It sold in 2011 for $8.8 million. The world’s largest gem-quality rough diamond, The Cullinan Diamond, is a Type IIa diamond. The rough diamond weighed 3,106.75 carats. It was eventually cut into 9 large stones and several smaller ones. Because the Cullinan Diamond was cut into separate pieces, it’s hard to say exactly how much it is worth, but when combined, all of the stones would be worth billions. The Pink Legacy diamond is a 18.96 carat fancy vivid pink diamond. This Type IIa diamond sold for $50.4 million in 2018."
According to "Why Are Certain Diamonds So Beautiful? They’re Super-Deep!" (2021): "What do the 3,106 ct. Cullinan, the 1,109 ct. Lesedi La Rona, and Elizabeth Taylor’s Krupp have in common? In addition to being some of the most famous and valuable diamonds in the world, they’re all Type IIa, which means they have no measurable nitrogen or boron impurities and are therefore chemically pure. Through his study of these diamonds at the GIA, research scientist Dr. Evan Smith and his colleagues have determined that most Type IIa diamonds – as well as just about every famous blue – are formed in what he calls the “super-deep,” the lower mantle of the Earth, more than 660 kilometers down. (Other diamonds form a mere 150 to 250 kilometers down.) “These huge flawless D color nitrogen-free diamonds don’t form the same way as other diamonds,” Smith says. “They come from four times deeper in the Earth than other diamonds. They don’t form anywhere else.” They even form differently. Type IIa rough is known to have a different shape than other rough. Yet, while these diamonds are created way under the Earth, they have been found all over the planet, everywhere from Africa to North America, Smith says. “Geographically, it’s hit and miss,” Smith says. “They don’t seem to follow the rules that normal diamonds follow.”"
Full size / Cartoon showing the growth zones for lithospheric diamonds (the first 250 km of depth) and super-deep diamonds (410–700 km depth). The grey part indicates a subducting slab that can penetrate into the lower mantle at depths greater than 660 km. (Cartoon by F. Chirico; Source).
Below excerpts are from "Type IIa diamonds and their enhanced economic significance" (2012): "Whilst the majority of natural diamonds are lithospheric there are deposits where a high proportion of the diamond population is from greater depths...
Size: Type I diamonds may reach considerable size. A good example is the Kimberley Octahedron, a yellow diamond showing some resorption, which at 616 carats is the largest octahedron ever found, and currently the 14th largest gem diamond ever recovered. It was found at the Dutoitspan Mine in 1971 and is now on display at the Mine Museum in Kimberley, RSA. However the largest diamonds ever found are dominated by Type II crystals, in contrast to the low global abundance of Type II diamonds. The largest single crystal gem diamond ever found is the Cullinan diamonds from the Premier (now Cullinan) found in 1905 and weighing 3,107 carats. The Cullinan has all the visual characteristics of a Type IIa diamond as do numerous other well publicized recoveries from this locality such as the Premier Rose (354 cts), the Centenary Diamond (599 cts) and most recently a 508 carat stone found in 2009. The Cullinan Mine is also noted for the occasional finds of rare blue Type IIb diamonds which contain boron and are semi-conductors as well as prized gemstones. Historically the long since (1971) defunct Jagersfontein Mine was also a noted and regular producer of visually recognizable Type II diamonds of which the Excelsior (995 cts) and the Jubilee (651 cts) are the most famous. Williams (1932) records that despite being a low grade ore body, Jagersfontein produced 54 diamonds larger than 200 carats in the period 1884 – 1930 including 6 over 500 carats.The size dominance of Type II diamonds is well demonstrated at Letseng la Terai in N. Lesotho by the fact that Type II diamonds >10.8 ct constitute 38% (in carat terms) of the diamonds in the main pipe and 69% in the satellite pipe (Bowen et al 2007, Moore 2009). Chinn (2008) estimated that Type II diamonds constituted 25% by weight of the diamonds in the AK-6 pipe in Botswana.
Crystal Form: Type II gem diamonds in contrast [to Type I diamonds] are highly resorbed crystals, never octahedra, often with fresh cleavage breaks and irregular form which appears to be the result of extensive resorption and susceptibility to cleavage.
Color: The relevant facts about colour with respect to Type IIa diamonds are that because they have no nitrogen and are particularly pure carbon, they frequently receive the very best colour grading for jewellery purposes (D on the GIA scale: essentially completely colourless)... Type IIa diamonds never become yellow. Type IIb diamonds are blue due to the presence of boron or brown or grey when deformed and also are never yellow. Type I diamonds in comparison may be visually colourless, but seldom are D colour and frequently are brown or yellow. In Ib diamonds the nitrogen is incorporated in the diamond lattice and the diamond acquires a distinctive canary yellow colour.
Value: Whilst large gem quality diamonds have always been prized for their value, that appreciation has been accentuated in recent years. This is best illustrated by prices paid for large Type II diamonds in the past 5 years. At the Cullinan Mine in 2009 a 508 carat diamond realized US35.3 million. In 2010 a Type IIb diamond was sold for over US$1 million per carat. At Letseng la Terai published data shows over 85% of the mine revenue is derived by Gem Diamonds from the sale of diamonds larger than 5 carats, predominantly Type IIa (Bowen et al 2007). Monthly sales values per carat have reached >$3,000/ct, with the best diamonds sold for more than US$50,000/carat. In 2006 the Lesotho Promise (603 cts) was sold for US$12.4 million and more recently the Lesotho Legacy realized US$10 million. Such returns have made it economically viable to operate an open-cast mining operation in difficult mountain terrain with recovered grades of under 2 carats of diamonds per 100 tonnes of kimberlite. At present market prices 1 carat of D colour Type II diamonds / 100 tonnes of ore can be a viable mining operation.
Economic Implications: The presence of D-colour large Type II diamonds in a deposit can be a mine-maker in that the presence of one 20+ carat diamond in 50,000 tonnes of host rock can convert to revenue in excess of US$20 / tonne of rock mined, which in some cases is close to mine operating cash flow costs. Consequently in the evaluation stage of a diamond deposit it would be advantageous to be able to predict the presence, size and abundance of Type II crystals. At present the only way to do that is to take a very large bulk sample such as is currently under way at the Mothae Kimberlite in N Lesotho by Lucara Diamonds.
Distribution of Type II Diamonds: The distribution of Type II diamonds is poorly recorded. The well known localities where they proliferate are or were Cullinan, Letseng la Terai and Jagersfontein all in southern Africa. However there are references in the literature to Type II occurrences in several Lesotho kimberlites, in particular at Mothae and Kolo, in South Africa (Koffiefontein, Bellsbank), Botswana (AK6, Jwaneng, Orapa), West Africa, India and South America. The recently recovered Spirit of Ekati from the Ekati Mine in the NWT, Canada and the Star of Sierra Leone have the visual appearance of a Type II diamond. So these important diamonds have a wide global footprint.
Discussion: [...] However elsewhere (e.g. Ekati) a high proportion of the run-of-mine production is octahedral [i.e. Type I], yet the Spirit of Ekati is anhedral [i.e. Type II]. Cullinan Mine and AK6 in Botswana both also have diamonds with a wide variety of crystal forms ranging from octahedra to stronger resorbed forms. Yet the Type II crystals are uniformly irregular and anhedral.Type II diamonds define a size distribution that is distinctive from the run-of-mine size distribution. This suggests a separate origin for the Type II diamonds.
Concluding Remarks: Given that they constitute <2% of the world’s diamonds, Type II crystals are overrepresented in the world’s largest known gem diamonds. Their distinctive appearance, great purity and lack of association with lithospheric source rocks leaves open the possibility that they are sub-lithospheric in origin..."
According to "Type IIa Diamond Formation" (2015): "Large type IIa diamonds are found as isolated crystals in diamond-poor kimberlite sections, completely lacking small diamond crystals. It is possible to conclude that the large irregular stones represent very late-crystallizing megacryst phases in pegmatitic veins, which crystallized from kimberlite magma injected into fractures in the mantle wall rocks surrounding the main parent kimberlite magma body at pressures and temperatures nearly graphite-diamond boundary."
Full size / Famous Type IIa Diamonds. Shown here: (1) The De Beers Millennium Star | 203.04 carat, (2) The Lesedi la Rona | 1109 carat, (3) The Koh-I-Noor | 105.60 carat, (4) The Pink Legacy | 18.96 carat, (5) The Idol‘s Eye | 70.21 carat, (6) The Cullinan I | 530.20 carat, (7) The Graff Venus | 118.78 carat, (8) The Agra | 28.15 carat. Images and information complied by Reena Ahluwalia. (Source)
Today´s news-release from Arctic Star:
Arctic Star Reports, Nitrogen Free Diamonds, Further Encouragement that Sequoia may have >50ct Diamonds
• Analysis of 12 >0.3mm diamonds, recovered in 2021 from the Sequoia kimberlite complex shows 50% are nitrogen free type IIa diamonds
• This result adds to a number of lines of evidence that this kimberlite complex has the potential to carry >50ct gems, indicator mineral chemistry collaborates with this, along with the diamond size distribution and the diamond descriptions (all described as clear white).
• Further drill definition is underway, this work will aid plans for a future bulk sample to recover >1500ct of commercial stones.
May 17th, 2022 Vancouver, British Columbia – Arctic Star Exploration Corp. (“Arctic Star” or the “Company”) (TSXV: ADD) (Frankfurt: 82A2) (WKN: A2DFY5) (OTC: ASDZF) is pleased to announce that has received the results of a diamond type study based on twelve >0.3mm diameter diamonds retrieved by caustic fusion analysis of the Sequoia Kimberlite in 2021, on is Diagras diamond property, NT
The diamonds were studied at the Saskatchewan Research Council Diamond laboratory in Saskatoon, (an ISO/IEC 1705 Standard lab), using Fourier Transform Infrared („FTIR“) Spectrometry. This type of spectrometry is used to determine the concentration and aggregation state of nitrogen within the diamonds. Diamonds are broadly divided into two types (I and II) based on the presence or absence of nitrogen impurities and further subdivided according to the arrangement of nitrogen atoms (isolated or aggregated) and the occurrence of boron impurities.
The results show that 50% of the diamonds are nitrogen free type IIa diamonds, 33% Type IaA, and 17% Type IaB. See Figure 1 showing a pie graph depicting the results. This is in contrast to the global distribution where it is estimated Type IaA dominates 96% and Type IIa diamonds only make up 2%.
Figure 1, Diamond Type distribution from Sequoia Kimberlite Caustic Fusion, Left, Estimated global distribution of these diamond types right.
Only a small number of active diamond mines regularly produce Type IIa diamonds with the most significant of these being Letseng-la-Terae (Letseng Mine) in the Kingdom of Lesotho and Karowe in Botswana. While Letseng is a low grade (1.5-3 cpht) kimberlite and Karowe approximately (15 cpht), they are probably the most prolific source of large high-value Type IIa diamonds, which contribute to making Letseng and Karowe highly economic deposits. The Koloa pipe, part of the Ekati mining complex, 34 kilometers west of the Sequoia kimberlite complex is also known to contain these types of diamonds.
Type IIa diamonds contain no nitrogen or boron impurities and are frequently either top white colours (D, E, F, or G) or shades of brown. Many pink and brownish-pink diamonds are also Type IIa. Type IIa diamonds typically have an anhedral crystal shape and exhibit a range of elongated, distorted, or irregular morphologies. Many high-value, top colour, large specials (greater than 10.8 carats) are Type IIa diamonds, which include all ten of the largest known rough diamonds recovered worldwide, from the 726 carat Jonker to the 3,106 carat Cullinan. Interestingly inclusion studies find that the majority of these large stones have come from great depth.
On September 9th, 2021, Arctic Star released results of a study of the indicator minerals recovered from Sequoia, which were analyzed and interpreted by Chuck Fipke. Unusually abundant deeply sourced indicator minerals were reported ($DI indicators), and these are associated with >50ct large Type IIa diamonds from Leteseng, Karowe, and Ekati. This work thus predicted the presence of Type IIa diamonds, now confirmed by the FTIR.
Vice President of Exploration, Buddy Doyle, states: ”The presence of a significant proportion of Type IIa diamonds in the Sequoia kimberlite complex caustic fusion samples is another line of evidence of the potential to host plus 50ct, high value diamonds, backed up by the collaborative indicator chemistry and the relatively coarse, low gradient diamond size distribution. Finally, SRC describes all the diamonds as clear and white, this is unusual as most kimberlites have a mix with a high percentage of boart.”
Buddy Doyle continued, “Arctic Star is currently drilling the Sequoia kimberlite to outline its size and shape and obtain more diamonds from caustic fusion to further constrain the grade, which current guidance puts at between 20cpht to 70cpht. The diamonds recovered by this year’s work will also be analyzed by FTIR. The information gained will allow the design of a >1500 carat bulk sample, which could be retrieved early 2023. Once we have the diamonds from the large sample we will be able to determine the average value per carat, essential in understanding the economic value of this complex.”
The reader is directed towards these references which were used to guide this news release.
Breeding, C.M. and Shigley, J.E. (2009) The “Type” classification system of diamonds and its importance in gemology. Gems & Gemology Vol. 45 No. 2 pp. 96 – 111
Smith, E.M, Shirey, S.B., and Wang, (2017) The Very Deep Origin of the World’s Biggest Diamonds. Gems & Gemology Vol.53 No. 4 pp. 389-403
The Qualified Person for this news release is Buddy Doyle, AUSIMM, a Geologist with over 35 years of experience in diamond exploration, discovery, and evaluation. A Qualified Person under the provisions of the National Instrument 43-101.
About Arctic Star
Arctic Star is predominantly a diamond explorer, recently discovering 5 new kimberlites in the prolific Lac De Gras kimberlite field that supports 2 multi-billion dollar kimberlite mining complexes. The company also has a 958Ha Exploration permit containing several diamond-bearing kimberlites on its Timantti project, Kuusamo Finland. Arctic Star has optioned its Stein diamond project in Nunavut to GGL diamonds who plan work once Covid restrictions lift. The company continues to look for appropriate diamond opportunities elsewhere.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accept responsibility for the adequacy or accuracy of this release.
Cautionary Statement Regarding “Forward-Looking” Information
This news release contains “forward-looking statements” including but not limited to statements with respect to Arctic Star’s plans, the estimation of a mineral resource and the success of exploration activities. In this release it is not certain if the kimberlite discovered will be economic or not as this depends on many factors. Forward-looking statements, while based on management’s best estimates and assumptions, are subject to risks and uncertainties that may cause actual results to be materially different from those expressed or implied by such forward-looking statements. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Factors that could affect our plans include our potential inability to raise funds as intended, and in such event we may require all funds raised, if any, to be used for working capital rather than the intended uses as outlined. Accordingly, readers should not place undue reliance on forward‐looking statements. Arctic Star undertakes no obligation or responsibility to update forward‐looking statements, except as required by law.
July 6, 2021: “New Diamond Discovery in Canada Now Official: Premier drill results from Arctic Star confirm Sequoia kimberlite to host diamonds“ (Web)
Arctic Star Exploration Corp.
1100-1111 Melville Street
Vancouver, B.C. V6E 3V6, Canada
Phone: +1 604 689 1799
Shares Issued & Outstanding: 208,978,844
Canadian Symbol (TSX.V): ADD
Current Price: $0.09 CAD (05/17/2022)
Market Capitalization: $19 Million CAD
German Symbol / WKN (Tradegate): 82A2 / A2PV9M
Current Price: €0.069 EUR (05/17/2022)
Market Capitalization: €14 Million EUR
Stephan Bogner (Dipl. Kfm., FH)
8260 Stein am Rhein, Switzerland
Disclaimer: This report contains forward-looking information or forward-looking statements (collectively "forward-looking information") within the meaning of applicable securities laws. Forward-looking information is typically identified by words such as: "believe", "expect", "anticipate", "intend", "estimate", "potentially" and similar expressions, or are those, which, by their nature, refer to future events. Rockstone Research, Zimtu Capital Corp., and Arctic Star Exploration Corp. caution investors that any forward-looking information provided herein is not a guarantee of future results or performance, and that actual results may differ materially from those in forward-looking information as a result of various factors. The reader is referred to the Arctic Star Exploration Corp.’s public filings for a more complete discussion of such risk factors and their potential effects which may be accessed through the Arctic Star Exploration Corp.´s profile on SEDAR at www.sedar.com. Please read the full disclaimer within the full research report as a PDF (here) as fundamental risks and conflicts of interest exist. The author, Stephan Bogner, holds a long position in Arctic Star Exploration Corp. and is being paid by Zimtu Capital Corp., which company also holds a long position in Arctic Star Exploration Corp., whereas the featured company Arctic Star Exploration Corp. pays Zimtu Capital Corp. for the preparation, publication and additional distribution of this report.