Argyle Lot numbers are one of the misunderstood aspects of pink diamond procurement. As Argyle’s operations have evolved and grown, so to has the Argyle Lot number. It was once applicable only to Argyle pinks and blues; now Argyle yellows, Argyle whites and even Argyle champagnes and cognacs can be assigned an Argyle Lot number which supports the claim of origin.
What is an Argyle Lot Number?
The general definition of an Argyle Lot number is that it is a unique number generated and assigned by APD (Argyle Pink Diamond, Rio Tinto). Argyle Lot numbers are created for parcels of small diamonds, mixed parcels (large and small diamonds), single diamonds and rough (uncut) diamonds. These numbers are kept on file at APD and are used to verify the cut, colour, size, clarity and time the diamond was certified. For Argyle white, champagne and cognac diamonds, it also confirms the size of the rough diamond before it was cut.
Interestingly, Argyle Lot numbers are not sequential and cannot be interpreted or decoded. For example, you cannot say all 6P colour graded diamonds start with the numbers “355.” This randomness ensures that lot numbers cannot be guessed or gamed. Whilst, Argyle Lot numbers will always be stated on an APD brifka (parcel paper) and APD certificate, they may or may not also be appear on an independent gem laboratory certificate, third party seller certificate, tax invoice or laser engraved on the diamond. The word “brifka” has Dutch origins and refers to a folded envelope used to package diamonds.
A diamonds first “baby blanket.” This Argyle brifka (parcel paper) shows the Argyle Logo (APD), Argyle Lot Number (43300), carat size (.10 Cts), clarity (SIAV), cut (OVL) and colour (6PR). For security reasons, the data on this brifka has been modified. (Photo: Sylvie Dibbs)
The Argyle Lot number lives on in other ways. Here an independent gem laboratory certificate states the Argyle Lot number in the comments section. The information on this certificate has been modified. I have changed the numbers to conceal the real Argyle Lot Number. (Photo: Sylvie Dibbs)
Argyle Lot Numbers for Parcels of Small Diamonds (Melee).
Parcels of small diamonds are organised by cut and carat weight range, then graded by colour. If the brifka is issued by APD, think of it as the diamond’s first baby blanket or swaddling cloth. This original brifka will have the APD logo, barcode and lot number. It confirms the colour, parcel size and carat weight range of the diamonds contained within. These diamonds will then be sold individually and the Lot number may be reproduced on the seller’s own documents, own certificates or stated on the independent gem laboratory certificate. These numbers are usually not disclosed until the diamond is sold. Having the number stated on documentation associated with the sale of the diamond adds to its re-sale value, unlike diamonds with no Argyle lot number.
Argyle Lot Numbers for Mixed Parcels of Diamonds.
Mixed parcels tend to be “older stones,” ones that were unearthed by Argyle earlier in the mine’s lifetime. These parcels are called mixed because they have a range of differing sizes, a general colour grade and general clarity. An example of such a parcel would be recorded in the APD database as a “Parcel of Light Pink Rejection Stones.” These may be a parcel of a few large stones, or a parcel of smaller diamonds that have many colour grades grouped together or even a few mixed cuts parceled together. These parcels are fantastic because they were created at an earlier time, when Argyle had access to a vast amount of pinks to pick and choose from. They would be incredibly strict as to what would be deserving of a certificate or included in a finely graded parcel. Fast forward years later, with the sunset years of APD approaching, what was once rejected would now most likely be given an APD certificate and laser inscription. They now cast a much wider net, opening up the standards as to what deserves a certificate and what is considered pink. New colour grades were invented by APD and introduced into the colour chart such as “NCP” (Near Colourless Pink) which is lighter than 9P. Before that, 9P was the lightest pink grade on the colour chart, and even earlier than that, 7P was the cut off for the lightest pink … you get the picture.
Argyle Lot Numbers for Single Stones.
Single diamonds have Argyle Lot numbers which are also referred to as their “certificate number” because it is the exact same number stated on the APD certificate and laser inscribed on the diamonds girdle (if the diamond is laser inscribed). Older Argyle certificates have a separate Certificate Number and an ID Number. In this case, the ID number is the Argyle Lot Number. APD began laser inscribing the lot numbers on large single diamonds sized 0.20cts and above in 2005. Before this, large single diamonds had only a certificate and no laser inscription. Over the years, APD have also shifted the parameters of what is classified as a “single” diamond. From 2009 onwards, it was sizes 0.15cts and above. Diamonds sized between 0.08–0.14cts would be parceled together, sharing a single Argyle Lot number. From the end of 2016 and onwards, though, diamonds sized between 0.08ct-0.14cts have no longer been parceled collectively, but are instead separated into single diamonds, in their own brifkas with individual certificates and laser inscriptions. This is why older diamonds on the market between 0.08 and 0.14cts only have an Argyle Lot number with no certificate or laser inscription. This can cause confusion and sometimes suspicion with people unfamiliar with the history of Argyle.
An APD Certificate circa 2011. Note the Certificate Number (4444) and the ID Number (58000) are different. In newer iterations of the APD certificate, there is no Certificate Number, only an ID Number. The ID Number is also the Argyle Lot number. For security reasons, the data on this certificate has been modified. (Photo: Sylvie Dibbs)
Argyle Lot Numbers for Yellow, White, Champagne & Cognac Diamonds.
Argyle yellow, white, champagne and cognac diamonds emerged later in the life of the mine as distinct Argyle products. Previously, the focus was on pinks and blues, with the other colours being absorbed into diamond supply chains around the world, forever losing their Argyle birthright. Now these coloured diamonds are emerging with their own Argyle Lot numbers. For example, the lot numbers for yellow diamonds start with the letter “A” followed by a sequence of numbers, while white Argyle Lot numbers are prefixed with “ARGRT” (an acronym for Argyle Rio Tinto). Argyle champagne and cognac numbers are just like the pinks and blues, they comprised of a sequence of numbers and do not have any letters incorporated. Please note, the “Check Authenticity”’ page of the Argyle Pink Diamond official website is only for laser inscribed diamonds. To check the any other Argyle Lot number, you must email APD direct at email@example.com
A facsimile of a certificate of authenticity produced by a third party seller. In this case, the seller is also a manufacturer and has cut the rough. The Argyle Lot Number is stated on their own certificate. This number was given to the supplier by APD. Note they have laser engraved the word “ARGYLE” on the diamond with their own reference number, not the Argyle Lot number. For security reasons, the data on this certificate has been modified. (Image: ACD)
Argyle Lot numbers are a dynamic and fascinating part of Argyle’s history. The changes to classifications and inventions of new standards not only reflect the growing value of Argyle diamonds over the years but also the strengthening of the Argyle brand. For me, it also beautifully reflects the lifespan of the Argyle mine and the hard fiscal reality that the gilded jar has run out of cookies: now every morsel is said to be valuable, every last crumb is more delicious than the last.