The Mondiamo evaluation process


Our team of experts brings together deep industry experience and a rigorous scientific approach to diamond jewelry evaluation.

You’ve received a guaranteed offer range from Mondiamo, got your free, no commitment shipping kit and your diamond jewelry is on its way to our evaluation center. Now you’re wondering, what happens next?

The guaranteed offer range is the price we commit to paying you before we even see your diamond jewelry. More than 90% of our customers receive a final offer price higher than the midpoint of the guaranteed range.

A Mondiamo shipping kit is free, safe and fully insured

Every item that is sent to us is unpacked by a certified gemologist while being
captured on video.


A FedEx package, delivered to our evaluation
center in New York

Your fully insured diamond jewelry arrives via FedEx overnight delivery. As soon as it arrives, it’s checked into our system by our inventory manager and an email notification is sent to you.

We take your trust and security seriously. That’s why every item that is sent to us is unpacked by a certified gemologist while being captured on video.

The information we obtain from the Diamond Grading Report is important, but not enough to determine the accurate value of your diamond. Therefore, we have multiple certified gemologists review your item. Here are some of the things we look at:

The DeBeers DiamondSure machine
  • Authenticate the item and confirm the diamonds’ 4C’s (cut, carat, clarity, and color).

  • Measure the brilliance, fire, and scintillation of the diamond using a controlled light environment.

  • Test the diamond on the DeBeers DiamondSure machine and the DeBeers SYNTHDetect machine to ensure
    it is natural and not synthetic or treated.

  • Measure the fluorescence of the diamond under UV light.

  • Check for damage or wear and tear using a gemological microscope at 60x magnification.

  • Assess the value of the precious metal and gemstone composition of the setting, if applicable.

  • Measure the diamond on a Sarine machine to determine if re-cutting the diamond can add value.

A diamond, unset from the mounting

Next, your diamond jewelry and completed evaluation checklist are passed to our diamond specialist who is responsible for determining the final offer for your item. There are a number of elements our diamond specialist takes into consideration, such as global diamond market demand and if re-cutting the diamond can add value.

Occasionally we’ll need to unmount a diamond from the setting in order to complete our inspection. In these rare cases, we always call our customers first to explain the particular reason why this needs to be done and get their written consent before proceeding.


A loose diamond examined by our Lead Diamond Buyer under a 10X loop

There is over a 90% probability that you will receive a final offer higher
than the midpoint of the guaranteed range


In most cases we’ve already provided you with a guaranteed offer range and our evaluation determines the final offer within that range. In other cases, we now have enough information to provide you with an accurate offer. Either way, we’re always focused on maximizing the value we can offer you for your diamond jewelry.

Based on our statistical model, there is over a 90% probability that you will receive a final offer higher than the midpoint of the guaranteed range we originally shared. You’ll get an email asking you to log in to your account where you’ll be able to view and accept our final offer.

Accepted offers are typically paid on the same or next business day. As part of the regulatory requirements of second hand trading, we are required to ask for an ID and a proof of address (e.g. a utility bill) before processing your payment.

Should you choose not to sell your diamond jewelry to us, we’re happy to return your item, free of charge, no questions asked. With Mondiamo’s evaluation process, there is no commitment or cost to you.

We pride ourselves in being transparent about our process. If you’re ever unsure about anything, just ask. We’re here to help.