1. The Priceless Crown Jewels: Koh-i-Noor & Cullinan I
At the pinnacle of diamond history stand gems whose cultural and historical value far exceeds any monetary figure. The legendary 105.6-carat Koh-i-Noor ('Mountain of Light') originated from India's Golconda region and is celebrated for its Type IIa crystal purity.
The 530.2-carat Cullinan I ('Star of Africa'), cut from the massive 3,106-carat Cullinan rough discovered in South Africa in 1905, remains the largest top-quality white cut diamond in existence.
"The world's most valuable historical diamonds are overwhelmingly Type IIa—free of nitrogen impurities and exhibiting pure crystalline transparency."
2. World Record Auction Sales: Pink Star, Oppenheimer Blue & Graff Pink
When examining open-market auction transactions at Sotheby's and Christie's, fancy color diamonds set extraordinary per-carat price benchmarks.
The CTF Pink Star—a 59.60-carat Fancy Vivid Pink Type IIa diamond—holds the world auction record for any jewel, selling for $71.2 million ($1.19M per carat) in 2017. Similarly, the 14.62-carat Oppenheimer Blue fetched $57.5 million, highlighting intense global demand for vivid blue boron-doped diamonds.
- 1. The Koh-i-Noor (Priceless / Estimated $1B+): 105.6ct Golconda Type IIa oval cut.
- 2. The Cullinan I ($400M+): 530.2ct Pear Cut, set in the Sovereign's Sceptre.
- 3. The Hope Diamond ($250M-350M): 45.52ct Fancy Dark Greyish-Blue Type IIb diamond.
- 4. The Pink Star ($71.2M): 59.60ct Fancy Vivid Pink Internally Flawless.
- 5. The Oppenheimer Blue ($57.5M): 14.62ct Step-Cut Fancy Vivid Blue.
3. Why Gemological Type IIa Purity Drives Multi-Million Dollar Values
Across all ten most expensive diamonds, a single gemological trait emerges: Type IIa classification. Free of nitrogen trapped inside the carbon lattice, Type IIa diamonds absorb zero visible light spectrum, achieving unmatched optical fire and transparency.
Through modern Chemical Vapor Deposition (CVD) technology in Surat, diamond growers now synthesize Type IIa crystals natively—making the exact atomic purity once reserved for royal crowns accessible to luxury fine jewelry houses globally.