Discover the Most Exceptional 6 Carat Diamonds: Type IIa Diamonds

History of Type IIa Diamonds

The Golconda region of India has been associated with the highest quality diamonds since the 4th Century BC. Golconda diamonds have historically been known for their exceptional clarity and colorlessness, but the technology to classify Type IIa diamonds wasn't formalized until the 1960s. Scientists finally had the technology to detect trace elements including nitrogen and boron in diamonds. Chemical classifications helped gemologists and jewelers to better understand the chemical properties of diamonds. Today Type IIa diamonds are also mined in other parts of the world including South Africa, Lesotho, Botswana, Angola, Zimbabwe and Canada. The mines in Galconda and Southern Africa continue to be the most important sources of Type IIa diamonds.

What is a Type IIa Diamond

About 95% of diamonds are Type Ia and contain trace amounts of nitrogen. Most diamond jewelry is made from Type Ia diamonds. Type Ib diamonds are often associated with intense canary yellow diamonds and are often used for jewelry. Type II diamonds are much rarer than Type I diamonds and have fewer inclusions and higher clarity than the more common Type I diamonds.

Type IIa diamonds are the purest form of diamonds with no measurable nitrogen or boron impurities. These diamonds are often colorless but can also be found in rare colors like pink, brown or blue. These are extremely rare and comprise less and 2% of all mined diamonds. These diamonds are formed under high-pressure and high-temperature conditions which can give the diamond higher clarity and brilliance. Gemologists describe Type IIa diamonds as having a stunning pure and clean visual appearance, almost like water or magical especially when the diamond is 10 carats or larger.

Type IIb diamonds contain boron which give them blue or grayish-blue color. Unlike other diamonds, Type IIb are semiconductors and can conduct electricity and are even rarer than Type IIa diamonds. The Hope Diamond is an example of a famous Type IIb diamond.

Famous Type IIa Golconda Diamonds

There are many famous Type IIa white diamonds from the Golconda Region including the three larger than 100 carats.

Koh-i-Noor

Koh-i-Noor, meaning "Mountain of Light," is one of the most famous Type IIa diamonds from the Golconda region. It was originally 186 carats when discovered and was cut to 105.6 carats. It was discovered centuries ago and has passed through the hands of multiple rulers. Currently, it is part of the British Crown Jewels, set in the crown of Queen Elizabeth The Queen Mother.

Darya-i-Noor

Darya-i-Noor, meaning "Sea of Light" is a pale pink, table-cut diamond that has been part of the Iranian Crown Jewels. It is 182 carats and is one of the largest cut diamonds in the world. It is believed to have originated from the Golconda mines.

The Regent

The Regent is 140.64 carats and was discovered in the early 18th century. This diamond is renowned for its pure, white color and brilliant cut. It was owned by multiple royals, including French King Louis XV, and is currently on display at the Louvre in Paris. Known for its exceptional fire and brilliance, the Regent is considered one of the most beautiful diamonds in the world.

Additional Famous Type IIa Diamonds

Learn more about additional famous Type IIa diamonds over 100 carats from Africa.

Lesedi La Rona

The Lesedi La Rona means “Our Light” in Setswana, reflecting its origins and significance to the local community. It is one of the largest gem quality diamond ever discovered at 1,109 carats. This diamond was discovered in 2015 in the Karowe Mine in Botswana. The Type IIa diamond was purchased in 2017 by Laurence Graff, founder of Graff Diamonds for $53 million. After an extensive cutting and polishing process that took over a year, Graff revealed the Graff Lesedi La Rona, a 302.37-carat emerald-cut diamond. This gem is now the largest square emerald-cut diamond in the world.

Great Star of Africa

Great Star of Africa or the Cullinan I is a 530.20 carat Type IIa discovered in 1905 at the Premier Mine in South Africa. The original rough diamond weighed a record breaking 3,106 carats, making it the largest gem-quality rough diamond ever found. The Cullinan diamond is a pear shaped diamond with 74 facets and was set in the head of the Sovereign’s Sceptre with Cross, part of the British Crown Jewels. The Cullinan I remains a prominent piece of the British Crown Jewels, housed in the Tower of London.

Winston Legacy

101.73-carat, D-color, flawless, pear-shaped diamond classified as Type IIa, indicating exceptional purity and transparency. Discovered in Botswana's Jwaneng Mine, the original rough diamond weighed 236 carats. After nearly two years of meticulous cutting and polishing, it achieved its remarkable final form.

Stunning Type IIa 6 Carat Diamonds Sold at Sotheby's

Sotheby's regularly sells impressive Type IIa 6 carat diamonds set as rings, pendants and earrings. If you are looking for the highest quality 6 carat diamond ring, consider a Type IIa 6 carat diamond. Take a closer look at rare Type IIa 6 carat diamonds sold at Sotheby's.

Graff 6.73 Carat Diamond Type IIa $540,000

In 2024, Sotheby's sold a Graff Oval diamond weighing 6.73 carats, D color, VS1 clarity, Type IIa ring for $540,000. The center diamond is flanked by triangle-shaped diamonds stated to weigh a total of 0.98 carat, are approximately F-G color, VVS-VS clarity. The Graff diamond ring sold for over twice the high estimate of $200,000 due to strong demand for oval diamonds. The increased popularity of oval diamonds, has made sourcing high quality diamonds over 5 carats very challenging for the past three years.

Round Brilliant Diamond 6.12 Carats Type IIa $425,000

In 2021, Sotheby's sold a round brilliant cut diamond weighing 6.12 carats, D Color, Internally Flawless, Type IIa ring for $425,000. The round brilliant diamond GIA certificate also states the diamond is Excellent Cut, Polish and Symmetry. While round brilliant diamonds are the most common, a Type IIa is still a rare find.

Harry Winston 6.01 Carat Type IIa Diamond $325,000

In 2020, Sotheby's sold a Harry Winston Pear Shaped 6.01 Carat, D Color, Internally Flawless, Type IIa diamond ring for $325,000. The ring also has tapered baguette accent diamonds, estimated to weigh a total of approximately 0.50 carat, are approximately D-E color, VS-VVS clarity.

Pear Shaped 6.21 Carat Diamond Type IIa $228,600

In 2023, Sotheby's sold a Pear shaped 6.21 carat diamond, D color, VVS2 clarity, Type IIa for $228,600. The accent diamonds are triangle shaped and are approximately E-F color, SI clarity.

Type IIa 6 Carat Diamond Price

Prices for Type IIa 6 carat diamond can vary widely but prices generally start at $200,000 but can range to over $500,000 for a white diamond depending on the shape and brand. Sotheby's recommends only purchasing a Type IIa 6 carat diamond with a GIA certificate that will include the classification as Type IIa. Most diamonds that are classified as Type IIa are generally D color and Flawless or Internally Flawless clarity and have excellent polish and symmetry. In general, a Type IIa diamond is priced at a premium to a Type I diamond but the overall quality and size of the diamond all factor into the price.

Once you have decided on a 6 carat diamond, it's worth going beyond the 4Cs and considering a Type IIa diamond. In addition to the pure visual appeal of Type IIa diamonds, the rarity of these diamonds also impact the long term value in the market.

Buy and Selling a Type IIa 6 Carat Diamond at Sotheby's

Once you have decided on a Type IIa 6 carat diamond, Sotheby's has a few ways to assist with the purchase of these rare and exceptional diamonds. Sotheby's often has impressive Type IIa diamonds available at auction, including 6 carat diamonds. Sotheby's is also able you to source Type IIa 6 carat diamond for immediate purchase. Once we have your budget range and preferred shapes, we can connect with our international network of suppliers to source a few options. A salon specialist can also arrange a private viewing once a Type IIa 6 carat diamond has been sourced. Given the rarity of 6 carat Type IIa diamonds, it could take a few weeks to view a few options and flexibility on the exact shape and carat weight is suggested to have more options.

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