In 1990, a Brazilian farmer found a peculiar stone in the Abaetezinho river near his field.
Little did he know that a decade later it will be one of the most famous diamonds ever. The rough stone he recovered weighed 13.9 Ct
and was later cut by William Goldberg diamond corp. into a 5.11 Ct triangular brilliant shaped diamond that received a natural fancy red color grading by the GIA. The GIA also declared it had internally flawless clarity.
It was purchased in 2001 by the famous London Jewish jeweler family of Mousaieff for $8m ($1.6m per Ct) and went on to be displayed at the historical “Splendour of Diamonds” exhibit at the Smithsonian at 2003, and thus gained worldwide exposure.
It is still regarded as the largest polished natural fancy red diamond, and its current price estimate exceeds $20m. Not a bad return on investment!
On a personal note I must add that I have received numerous purchase inquiries of this amazing diamond and being briefly acquainted with the Mousaieff family they don’t shop their important diamonds too much and will only negotiate once a truly awesome offer is on the table. So if you are short of those $20m, it’s a waste of time!
Scientifically speaking red diamonds are unlike other fancy color diamonds such as pink diamonds, yellow diamonds and blue diamonds all of which contain foreign element impurities (such as Nitrogen or Boron) within them that affect the way the light behaves within the stone. Natural fancy red diamonds (without any color modifiers) are absolutely pure in that aspect. What is believed (by the GIA and other researchers that had to settle for only a few specimens for examination) is that there is a deformation in the atomic level of these diamonds (caused by a phenomenon called “gliding”) results in the rich and beautiful color effect we all admire. This mystery obviously adds even more to the lure of these precious treasures.
In terms of color grading, there are several color modifiers and variations to natural red diamonds - purplish red, pinkish red, reddish pink, orangy red, reddish orange and reddish brown.
When it comes to pure red diamonds, there is no scale of intensity levels like in other fancy color diamonds (this also is true for black diamonds but they are mostly opaque). So a pure red diamond is only “Fancy Red”. No “fancy intense red” etc. This means any red diamond you might get (if you’re fortunate enough) is fully saturated and its color lies somewhere between orange and purple on the color palette. Some lesser pure variants can have different intensity levels such as “fancy dark reddish brown” or our beautiful 0.71 Ct fancy dark red-pink diamond but not in the predominant red ones (which can be easily distinguished by the fact that the “red” is the last word in the color description e.g “fancy purplish red”).
Red is so rare and pretty that even a tiny glimpse of it within a stone under the right lighting might add to its value tenfold.
See below example of this 1.52 Ct fancy dark reddish brown diamond - the beautiful interior red flares (which are only visible when the stone is moving facing a light source) make this one worth 5 times more than if it were just fancy dark brown.
Though it’s reported that only 1 out of 100,000 gem grade diamonds found has natural pure red diamond we are still lucky to have a few more notable ones out there. The opening of the famous Argyle mine in Australia in 1985 has contributed immensely to the supply of these rare stones (which before then could literally fit entirely on one's finger!). However, none of the Argyle reds is nearly as large of the Mousaieff diamond. The closest one is the Argyle Phoenix, the 1.56ct round brilliant cut diamond that was auctioned by Rio Tinto at its 2013 event and sold for more than $2m. This was the highest per carat price ever paid for an Argyle diamond. That 2013 auction was a real festivity for red diamond fanatics as it auctioned 3 more exceptional fancy red diamonds.
Still, when you look at the chart below that displays a breakdown of color descriptions of all diamonds that were auctioned in Rio Tinto's Argyle tenders between 1995-2014, you can clearly see that red diamonds are a tiny fraction.
A notion about rarity- some fancy color diamond experts rightfully claim that fancy red diamonds are not the rarest. That's because there are certain gradings that are even more rare to come by. For example, a "fancy vivid purple" diamond is something almost no one sees (I've seen, 1!). But that doesn't make purple diamonds more rare than red, there are many fancy pink-purple diamonds in the market.
The Hancock Red Diamond
Sold at Christie’s New York auction in 1987, this 0.95 Ct round cut diamond had the highest per carat closing price for any gemstone up to that moment in history, which got some noteworthy media exposure.
Kazanjian Red Diamond
Emerald cut deep ruby color weighs 5.05 Ct which makes it the world’s second largest red diamond. It has a very long and fascinating history since it was mined nearly a century ago and mistaken to be a poor quality diamond and later even a ruby. It was confiscated by the Nazis in WWII and after disappearing again in 1970 it was bought by the Kazanjian bros. Co of Los Angeles and is finally getting the adoration it deserves.
De Young Red Diamond
A 5.03 Ct round cut red diamond that comes in Third in terms of weight. It also was not appreciated and recognised as such a rare and important stone until it was picked up by a New England jeweller by the name of Sidney De Young at an estate auction and later was graded as a fancy red diamond. It is now on display at the Washington natural history museum, courtesy of Mr De Young.
The Rob Red Diamond
This small 0.59 Ct pear-shaped VS1 red diamond is believed to have the strongest color saturation of any red diamond ever examined and documented. At GIA, it’s still a “fancy red”…
Treated red diamonds
Some type II diamonds can be treated with HPHT process (multi-step treatment) to achieve red color. However, the color looks quite different than natural untreated ones (much more magenta) and are worth much less.
See photo below of a very nice 3.91ct Emerald HPHT red diamond. Worth about 80,000$, a natural one would have been estimated at over $15m.