Gigantic Gemstones on the Block

It has just been announced that the biggest, most valuable diamond in Australian history is to go under the hammer in Sydney on April 20. No, we don’t mean someone’s going to crush it into smithereens with a giant mallet or something Thor might wield around when he gets excited! No, that would be a great shame for such a fate to befall a super sparkler.

The rock is going to be sold to the highest bidder, as indicated by the fall of the auctioneer’s gavel (small hammer!).

Jewellery auctions can be pretty exciting. There are a range of different types of auctions which take place and include jewellery – from Police auctions, where confiscated/stolen property is sold to the public – through to extremely high-end auctions which may only feature a handful of incredibly valuable and/or rare items, such as the annual pink diamond sales.

The upcoming Sydney auction will be held at long standing Australian auctioneer Leonard Joel’s rooms in Queen Street Woollahra. It’s a fairly significant offering of all sorts of items, some of which will fetch very big bucks. The atmosphere will be at fever pitch we think, when lot 46 goes on the block. The expression ‘on the block’ has been used in auction rooms for hundreds of years and refers to an item going up for sale. Often it will be placed on a large plinth - for all to see - next to the dais or stage where the auctioneer is conducting proceedings.

Leonard Joel has said they are delighted to be “presenting the largest and most valuable diamond ever to be auctioned in Australia.” Lot 46 is a platinum and diamond ring, featuring a square, emerald cut diamond weighing a staggering 25.02 carats. Do you think it’s possible the wearer decided to sell because they were developing RSI in their ring finger from hauling such a ginormous girdle around town?

The item is catalogued (described) as:

A Spectacular Platinum and Diamond Ring. The Square emerald-cut diamond weighing 25.02 carats is claw set above a gallery pavé set with brilliant-cut diamonds, between shoulders decorated with a line of graduating baguette diamonds, the small diamonds together weighing approximately 3.25 carats, size M.


Gahcho Kué Diamond Mine, Kennedy Lake, Northwest Territories, Canada. The 25. 02 carat diamond was cut from a 47.961 carat rough.

Accompanied by a GIA report numbered 6214351034, dated 30 December 2020, stating that the 25.02 carat diamond is I colour, VVS2 clarity, laser inscribed

Estimate: $990,000 – 1,200,000


This auction will include pre-loved pieces from the big jewellery houses such as Cartier, Bulgari and Tiffany. Also up for grabs will be modest items from local designers. Some lots may have been family heirlooms, some are bought and sold regularly by collectors and dealers. Probably not all will sell on the night, though this sometimes does happen (called a white glove auction). Many will attract a flurry of bidding and be traded quite quickly, whereas some lots will involve lengthy, protracted bidding – which will most likely be the case with the diamond show-stopper, lot 46. Lots of people will be noting the lots – what they fetch, who is buying (if it’s possible to tell; sometimes it is, often it’s not). And everybody will be waiting to see what the final figure is when the precious pebble is peddled, as will we!

Quite a few huge diamonds have had their origins Downunder. The largest single diamond discovered in Australia was at the Merlin Mine in the Northern Territory, in 2003. The remarkable rock weighed 104.73 carats. The mine had only been operating for a relatively short time when this mammoth was unearthed. At the time it was valued at over half a million US dollars. The same mine yielded some other enormous diamonds, but after a while its overall output was just not living up to expectations, certain loan payments were not being met, therefore a liquidator was called in. Diamond mining can be lucrative if all goes well, but it can also be a rather risky business!

But although some of the most marvellous diamonds have been discovered in Australia, if they go to auction it’s usually overseas. The fact is that the most valuable diamonds and other gemstones - if they are sent for sale by the gavel - end up in New York, London, Geneva or Hong Kong.

Perhaps Leonard Joel’s lot 46 will set a new record for a diamond sold at auction in Australia? It looks very likely, which is really exciting!

The top 5 priciest diamonds to ‘go under the hammer’ are:

Number 1 – The Pink Star

The ‘Pink Star’ was originally mined in South Africa by De Beers in 1999; at the time it was called the ‘Steinmetz Pink’, as that was the famous diamond outfit who initially cut it (it had been twice the size when mined – and it took them over 20 months to sculpt it into the flawless example which was to capture the world’s imagination…) It weighs 59.60 carats and measures 2.69 by 2.06 centimetres. The Pink Star was sold by the international auction house Sotheby’s in their Hong Kong rooms in April 2017. Bidding went up to $US 83 million by the time the other bidders had dropped out, and the prize went to renowned jeweller, Chow Tai Fook. It still holds the record for the biggest flawless vivid pink diamond ever to be sold.

Number 2 – The Oppenheimer Blue Diamond

A blue diamond, which is very rare, also found first in South Africa. It’s the best example of its kind, radiating an unearthly blue hue and in astonishing proud rectangular form; it had belonged to the Oppenheimer family, who had operated the legendary diamond business De Beers. In May 2016 it fetched a whopping $58 million dollars at auction by Christies at the Four Seasons Hotel in Geneva, Switzerland. At that time it set the new record, which was to be surpassed not long after by the Pink Star.

Number 3 – The Wittelsbach-Graff Diamond

Another blue diamond - the Wittelsbach-Graff Diamond - has an amazing colour and a colourful history to match. It was found in the 1600s in the mines of Kollur, India. The first owners were the Nawabs of Punjab. In 1664 King Philip IV of Spain gifted it to his daughter upon her engagement. Through the centuries since then it has been lost, found, stolen, recovered, owned by various European royalty (including the Wittelsbach family of Bavaria – hence the name), other collectors and then wound up in the hands of Mr Laurance Graff (billionaire jeweller and businessman) in 2008. He purchased it in 2008 at Christies London, for $23.4 million, which was a record at that time. In 2011 Graff sold the diamond to Hamad bin Khalifa (Emir or ruler of Qatar) for a reputed $80 million.

Number 4 – The Graff Pink

Two years later Laurance Graff was rocking the house again when he acquired what would become known as the Graff Pink diamond at Sotheby’s Geneva for $46 million, in November 2010. The fancy intense pink is emerald cut with round corners, mounted on a platinum ring with two shield shaped diamonds on either side. It had once been in the possession of the American celebrity jeweller Harry Winston. Yep, you guessed it, Mr Graff’s 2010 purchase became the new world record price for a diamond sold at auction, and it is understood that he still owns it.

Number 5 – The Princie Pink

Another rare wonder from India, discovered well over 300 years ago. Its first owners were the royal family of the Indian city of Hyderabad. Much later it became known as ‘Princie’ after the son of the Maharaja of Baroda, one of the sub-continent’s wealthiest rulers. It is an extremely large and rare example of a pink diamond - at 34.65 carat cushion cut fancy pink – some consider it to be the third largest pink diamond in the world, after the Daria-i-Noor and the Noor-ol-Ain – both of which are components of the Iranian Crown Jewels. The second largest then being the abovementioned Pink Star. In April 2013 Christies New York sold it under the hammer for $39 million.