Few things excite collectors more than seeing the impossibly rare stones come to market.

Of course we can agree that all diamonds are a relatively rare occurrence in nature. The consensus across all areas of mining claims that 250 tons of ore must be mined to produce one single carat of diamond.

This also puts fancy color diamonds into context---only one fancy color diamond occurs for every 10,000 colorless diamonds mined.

Auction Updates

There’s plenty to keep up with right now on the auction front. In the March 19th edition of Rapaport News, managing editor Leah Meirovich reported—The Mediterranean Blue, a 10.03 carat modified cushion brilliant-cut, fancy-vivid-blue, VS2-clarity, type IIb diamond, will headline the May 13, 2025, High Jewelry Sale at Sotheby’s Geneva.

Details Matter

Each one of the descriptive details about the Mediterranean Blue heralds its rarity. While many know that the stone’s size and color place it in a class of its own, not all diamond enthusiasts are savvy about the type IIb classification.

Fewer than 0.01% of all diamonds are classified as type IIb. Simply put, type IIb diamonds are a rare category of stones possessing extremely low levels of nitrogen impurities---which are responsible for a yellowish tinge in a diamond.

This type also signals the inclusion of significant boron impurities which contributes to its blue tint.

Famous Provenance

The upcoming auction marks the exceptional diamond’s debut onto the global market. The stone hails from Petra Diamonds’ Cullinan mine in South Africa. The mine is renowned for producing the legendary 3,106 carat Cullinan diamond---the largest gem quality diamond ever recovered. The mine also has a reputation for producing blue diamonds, which are among the rarest shades on earth.

Recovered in 2023 as a 31.94-carat rough, the crystal was studied for more than a year before entering into a six-month manufacturing process, Sotheby’s explained. As with other nearly priceless stones, it is customary to study the crystal rough for months or even years prior to making the first stroke.

The massive Cullinan was studied for nearly 8 months prior to its initial cleaving. This thoughtful process allowed the cutter to optimize the rough, and plan for the largest stones with the greatest clarity as a result of this careful study.

LEIBISH Shares Insight

In that recent Rapaport report, addressing the possible $20M sale, they wrote:

“Leibish Polnauer, owner of Israel-based colored diamond manufacturer- Leibish & Co.,. believes the stone could fetch over $30 million, noting its exceptional quality, and the fact that the market for blues is not affected by the general downturn in the main diamond market.”

How Pre-Sale Estimates Work

Top auction houses often set low pre-sale estimates on headliners to stir up their bidder’s enthusiasm. Once the paddle goes up, it’s hard for a bidder to put it down—causing the anticipation to swell. And while many bidders are on the phone or using electronic bidding now, paddle fever is still a real thing.

Color Diamonds Stir Auction Prices

Fancy color diamonds, and in particular rare vivid blue stones continue to command impressive hammer prices at auction, underscoring their enduring appeal.

While all vivid blue diamonds are highly collectible, here are couple of notable examples to put the upcoming diamond into perspective.

The De Beers Blue: A 15.10-carat step-cut Fancy Vivid Blue diamond sold for $57.4M in 2022, earning approximately $3.8M per carat.
The Oppenheimer Blue: A 14.62-carat Fancy Vivid Blue diamond fetched $57.5M in 2016, equating to about $3.9M per carat.

So I figure that my $30 million dollar estimate for the Mediterranean Blue is not unrealistic at all. Fine fancy color diamonds are scarce and especially the subset of vivid colors---those are hard to come by.

From time to time, Important stones reappear at auction fetching far higher prices than they previously achieved. As serious collectors mature in their taste and understanding about the near priceless jewels, these soaring prices reflect that appreciation.

A Prominent Example is the Graff Ruby

Something similar happens with precious color stones which can sometimes become legendary treasures. Burmese ruby fits perfectly into this category.

Ruby mines situated in various parts of the world can produce some fine goods, Burmese ruby however, is in a class of its own. The cognoscenti call them freaks of nature—their traits are that unique. Their exquisite body color, plus their uncommon red fluorescence helps distinguish these coveted stones.

Top Burmese ruby also possess light-scattering rutile needles which produce velvety looking jewels unlike any found elsewhere. ‘Pigeon blood’ is the whispered name given to its magnificent coloration--and found only in Burma (now Myanmar).

So Beautiful He Bought it Twice

International news outlets confirm that London luxury jeweler Laurence Graff has paid a record 8.2 million Swiss Francs ($8.6M US) for a Burmese ruby. This was the top lot at a Sotheby’s Geneva auction recently marked by strong prices for fine diamonds and rare colored stones, Sotheby's confirmed

Graff, widely regarded as the "King of Diamonds", bought the 8.62 carat ruby for a second time, having first acquired it at an auction eight years earlier. It’s not unheard of for spectacular stones to come up again at auction.

Graff had named the 'Pigeon-Blood', (pure red with glints of blue) gem the "Graff Ruby" at the time.

Our Own Storied Diamonds

At LEIBISH, we’ve handled some exceptional vivid blue diamonds throughout the years. The finest one that I recall was a 3.30 carat Fancy Vivid blue pear shape which my son Shmulik, GG GI. acquired.

Come With me to a Private Transaction

The special event unfolded in a Swiss Bank. When the bank attendant first opened the box of an anonymous client—he took a moment to clear his throat and composed himself.

BLUE diamond LEIBISH
Shmulik Polnauer, GG, Photo courtesy Leibish & Co.

Then he removed three small parcels, placing each carefully in front our gemologist Shmulik who had just turned 28 years old.

He looked intently at the stones, placing two carefully in his left hand. Then he lifted the 3rd stone in his right hand, turning it slowly a few times, and looked the bank clerk in the eye.

The bank clerk gestured with his hand, and asked,

“how may assist you sir?”

“How much?”

“Three million dollars for the stone,” and added, “sir.”

“Would you like an offer?” Shmulik asked discreetly.

The clerk stood there stunned. This skinny kid looking no more than 17 years old, pulled an envelope out from his shirt pocket with LEIBISH printed on it and slipped the 3.30 carat vivid blue inside.

Closing the envelope back up carefully, he wrote a single line---$2 Million Cash.

“Sir, maybe you should get your father on the phone, first?”

“That is my offer,” Shmulik responded quietly. “You ask your client.”

Good Stone, Good Business

We bought the stone and resold it shortly thereafter to a well-known British jeweler.

Today that memorable blue diamond is worth 3 times what we paid for it just 13 years back.

So, if diamonds are forever-- Fine fancy color diamonds are forever after.