Diamonds should be much more expensive. Part 2- Sorting diamonds.

As I shared in my previous newsletter, my visit to a diamond mine in Namibia was a game-changer. The insights I gained from seeing the diamond sorting facilities in action have significantly deepened my understanding of the diamond market. I was truly impressed by the scale of the operation and the abundance of diamonds I saw and held.

For the first time, I experienced how heavy and cold diamonds are. Normally, I have a maximum of 100 smaller diamonds in my hands, but that is not enough to feel their weight and temperature.

Diamante er både kolde og tunge. Her er er nogle af de smukkeste diamanter fra Namdeb minen. Læg mærke til at de nærmest er farveløse. Billede af Niels Ruddy Hansen.

At the Namibia Diamond Trading Company (NDTC), all the diamonds mined in the diamond mine and from the sea are sorted. This is done by various sorting procedures that I could never have imagined. Approximately 1500 carats of diamonds are sorted every day.

The diamonds are roughly sorted at the mining site itself.

As you may remember from the previous newsletter, they are vacuumed into large closed tankers and transported to the sorting facility we visited.

De 1500 Carat diamanter der er blevet udvundet på en dag af Namdeb minen, skal nu sorteres. Billede af Niels Ruddy Hansen.

At the sorting facility, the diamonds are sorted using different methods.

  • Crushing and sorting. The material is further crushed to free the diamonds from surrounding rocks and minerals.
  • Heavy Media Separation (HMS) This process uses a heavy liquid to separate heavy minerals (like diamonds) from lighter materials.
  • X-ray sorting: X-ray radiation is used to identify and sort diamonds after HMS. Diamonds fluoresce under X-ray radiation, making them quickly identify and automatically separate.
  • Finishing: After X-ray sorting, the remaining materials are manually inspected to ensure that all diamonds have been removed. This step includes manual sorting using microscopes and other visual aids.
All the small stones that the diamonds may have been sucked up with are sorted out.

The diamonds are then sorted, first by machine and then by hand.  The diamonds are sorted by shape, colour, clarity and weight. Exactly as we know it in relation to the 4 C’s of cut diamonds.

  • Cut – cutting
  • Colour – colour
  • Clarity – clarity
  • Carat – size
Manually sorting the diamonds. Foto Niels Ruddy Hansen

The largest diamonds, i.e. all those that can become polished diamonds over 5 carats, are assessed individually by highly experienced diamond graders. It can take several months to evaluate these diamonds because it is essential to know precisely which polished diamond they can produce. In that assessment, the shape of the rough diamond and the inclusions in the diamond must be taken into account.

The uncut large diamonds are on white paper with reference stones in familiar colours inside the small circles. Photo Niels Ruddy Hansen.
More uncut diamonds. Photo Niels Ruddy Hansen

Once the diamonds have finally been sorted, they are sold and sent to cutting centres, where diamond cutters cut and polish them.

After all this, diamond dealers like me buy the diamonds and have them set into beautiful jewellery.

It’s an incredible process that diamonds go through before they are set in jewellery.

They were created deep in the earth’s interior trillions of years ago, then shot out to the surface of the earth millions of years ago, and have now been found, dug up, sorted, cut, polished and finally set in jewellery.

Understanding the journey of diamonds has made me appreciate my diamonds even more, and I hope you do too. 

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