What can I sell at Catawiki's Diamonds auctions?

Diamonds Premium Positioning

At Catawiki, we auction diamonds of premium quality which are hard to find and appealing to passionate diamond enthusiasts and collectors.

Because potential buyers come to Catawiki looking for special and rare diamonds, our in-house experts select every piece for our auctions, ensuring they are of premium quality and are presented in the best possible way.

We do this because we aim to keep our bidders excited, allowing them to find the pieces they’re interested in and ensuring our sellers have great selling experiences.

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Product Guidelines

At Catawikiwe auction diamonds gathered from all corners of the world.

For our auctions, we seek and select:

  • cut diamonds as well as rough diamonds that are of  quality, in all colour ranges except opaque
  • in the case of rough diamonds, diamonds that are always accompanied by a gemmological certificate, of valuable appearance and suitable for jewellery mounting
  • diamonds of all clarities, except diamonds with inclusions causing opaqueness (for other exceptions see the Clarity Table), of decent condition and that have a sufficient quality in cut and clarity to be mounted in jewellery
  • diamonds that are accompanied by a trusted gemmological certificate
  • lots that have a minimum estimated value of €150

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Certified natural diamonds of premium quality

For our diamond auctions, we seek a wide range of natural diamonds that are accompanied by a trusted gemmological certificate (see details further on).  This includes:

White diamonds

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Colour treated diamonds 5.PNG
Natural fancy colour (NFC) diamonds 6.PNG
Clarity enhanced diamonds 7.PNG

Diamond cuts

For our dedicated diamond auctions, we select cut diamonds that are ready to be mounted in jewellery:

This includes cuts such as:

  • Brilliant cut
  • Fancy cut
  • Laser cut
  • Old cut
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Cuts that are not suitable are:

  • 8/8 single cut
  • Swiss cut
  • Damaged and broken cuts

Colour conditions

For this auction, we accept diamonds that are of a suitable colour or in more specific terms, belong in a certain colour range. This means that the items suitable for this auction are:

  • White D to Z
  • Natural fancy
  • Colour treated (CT) irradiated/HPHT
  • CT black(ish) (opaque)
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Suitable D colour Suitable F colour Suitable HTHP treatment
     
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Suitable fancy colour Suitable fancy colour Suitable treated item

Although we find a wide range of colours suitable, the following is not suitable for our auctions:

✗       Colour coated

Clarity conditions          

For this auction, we accept diamonds that are of suitable clarity or in more specific terms, belong in a certain clarity range. This means that the items suitable for this auction are:

  • FL to I3
  • AIG (IL) clarity grade IF to SI2Note: I1, I2 & I3 can only be accepted without a reserve price
  • Clarity I1, I2 & I3 have a minimum total carat weight requirement (see next section for details)
  • Fracture filled (CE) clarity grade IF to SI1
  • Laser drilled clarity grade IF to SI1

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In terms of clarity, there are certain ranges that do not live up to our standards and these are:

✗   Fracture filled (clarity treatment (CE) clarity grade SI2, I 1/2/3

✗   Laser drilled (clarity treatment) clarity grade SI2, I 1/2/3

✗   Heavy inclusions causing opaqueness

Clarity conditions         

The following standard treatments are accepted for our selected diamonds:

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Accepted standard treatments

The following standard treatments are accepted for our selected diamonds:

  • Irradiation treatment, which leads to a variety of coloured diamonds (for example: yellow, orange, pink)
  • HPHT (high-pressure, high-temperature) treatment
  • Fracture filled (CE) with clarity grade ranging from FL to SI1
  • Laser drilled with clarity grade ranging from FL to SI1
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Irradiation treatment HPHT treatment

The following standard treatments are not suitable for our selected diamonds:

✗    Fracture filled with clarity grade SI2, I 1/2/3

✗    Laser drilled with clarity grade SI2, I 1/2/3

✗    Colour coated

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Colour coated treatment

Condition

For our auctions, we accept diamonds that are natural, undamaged and have a decent clarity. This means that the items submitted:

  • may present small damage, but the seller needs to declare these damages and there should be a possibility of repair through recutting or repolishing

✗  Submissions with damages that would lead to them breaking during the setting procedure are not suitable for our auctions.

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Damaged diamonds

The expert reserves the right to reject a submission if the scratches/damages surpass a level and the value of the diamond is affected.

Authenticity / Certification Requirements

Buyers are more likely to bid on your lot if they know it’s certified as being authentic.  This is why we always ask to see certificates from trusted gemmological institutes for all our submissions.

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To help you have a better understanding of the level of certification required for our diamond auctions, we have the following list of accepted institutes:

Examples of trusted authentication certificates

These following certificates are generally considered to carry sufficient details to be trusted by our experts:

  • GIA
  • HRD
  • IGI
  • AIG (B)
  • IGE
  • EGL (US)
  • NEL
  • IGI Milano
  • IIDGR (De Beers)
  • AIG (IL) only for clarity grade FL to SI

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Please be aware that we do not consider the following certificates to be suitable:

  • IGL
  • AnchorCert
  • DGI
  • CISGEM
  • IJGC
  • EGL (B)
  • GIL
  • CG

 

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On the off-chance our experts consider the certificate to be overrated, the submission might need further clarification from the seller.

Register as a seller to begin selling your diamonds on Catawiki, then start submitting your objects for auction right away.