Type IIa diamonds are the most valued and the purest type of diamonds. They contain either very little or no nitrogen atoms in the crystal structure. White stones are exceptionally colorless and fancy colored diamonds are often found with a brown, purple, blue, or pink tone. They represent only 1% - 2% of all mined diamonds in the world.
What makes the Type IIa diamonds even more special is that they are “super-deep” diamonds. Most Type IIa diamonds originate from extreme depths in Earth’s mantle, a depth between 360 and 750 km. To put it in context, most diamonds are formed between 150 to 230 kilometers below the Earth's crust.
In the world of mined diamonds, Type IIa are so rare that they command a 5% to 15% premium, when they can be found.
One of the most well-known examples is the “Elizabeth Taylor Diamond” (formerly known as the “Krupp Diamond”), a 33.19-carat Type IIA diamond.
Purchased for $300,000 in 1968 by Richard Burton, the ring became one Elizabeth Taylor’s most cherished white diamonds; one she wore nearly every day. Of the ring, she once said, “[It] gives me the strangest feeling for beauty. With its sparks of red and white and blue and purple, and on and on, really, it sort of hums with its own beatific life.” The Asscher-cut diamond ring recently sold at auction for a whopping $8.8 million.
Other iconic historic Type IIa diamonds include the Cullinan, the Lesedi La Rona, the Koh-I-Noor, the Darya-I-Noor, the Archduke Joseph, the Regent, the Agra, The Star of the South, The Winston legacy and the Beau Sancy. Type IIa diamonds also have a famous historic connection with Golconda diamonds mined from the historic Kingdom of Golconda in India.