Bringing Diamond Grading into the 21st Century

Today we deploy the most advanced proprietary technology and are passionate about the science of diamonds.

At the International Institute of Diamond Grading & Research, we understand the science of diamonds. Combining over 120 years of diamond industry experience with the most advanced technology, we evaluate diamonds of every size and quality.

The appeal of diamonds is complex and exciting, however, on a practical level, it is our gemologists’ responsibility to impose a rational approach to the stones they consider.

Using specially developed, proprietary

instruments and technology we impartially assess every diamond according to criteria based on the 4C’s of Colour, Cut, Carat Weight and Clarity.

When buying a diamond, we believe that its credentials are as important as its setting. Every diamond we assess receives either our official Diamond Grading Report (complete with a detailed diagram of the diamond and any visible inclusions plotted), or a more concise Diamond Identification Report.

For more information please contact us:

T: +44 (0) 207 858 7887


Making the Grade

Using our secure online submission process we assign a unique reference number to every diamond. The International Institute of Diamond Grading and Research only accept naturally occurring diamonds of all colours and cuts.

Grading Reports

We issue Diamond Grading Reports and Diamond Identification Reports for any unset, natural, untreated diamonds weighing a minimum of 0.10ct. We grade every clarity and all colours including fancy colours.

Table & Gridle Inscriptions

The International Institute of Diamond Grading & Research are spearheading confidence in diamond integrity. We are the only lab in the world to offer the option of either a table or girdle inscription on any diamonds we grade.


We are proud to offer a sealing service on request.

Fees and Standards

The International Institute of Diamond Grading & Research grading standards, fees and procedures are available for you to download for free below. These will give you a comprehensive overview of our grading services, the charges and the procedures on how to submit diamonds to one of global laboratories.

“First Class Grading Service.”

Michael Rawlinson - CEO National Association of Jewellers

“World class grading service reinforcing confidence in the UK diamond industry”

Victoria McKay - COO London Diamond Bourse

“Best in the business.”

Lucy Reece-Raybold - Executive Director of Business Development Company of Master Jewellers

Contact Us


Map Data


Where will this be carried out?

At the IIDGR Surat laboratory the IIDGR laboratory in Antwerp and the IIDGR laboratory in Maidenhead, UK.

When will the service start to be offered?

The service is now running from all 3 of our laboratories in Surat, Antwerp and Maidenhead.

What will the cost of the service be? Will there be any price breaks for higher volumes?

Pricing will work on a sliding scale from 0.01cts through to 0.20cts. Full price lists in Indian Rupees and USD can be found on the website.

How will this work practically? How do we get goods to you? Are there any restrictions on how goods are submitted?

There will be a web-service for potential clients to sign-up to, complete their details, receive a log in and submit their goods to our system. Following that, the goods may be physically sent to the laboratory for testing.

What will I get back from the facility and what level of assurance will it provide me (i.e. sealed packet etc.)?

The client will receive sealed, tamper-evident parcels which will clearly state what the content is and the result of the testing.

Who do you think should be responsible for the submission of the parcel – the buyer or the seller in a polished transaction?

This decision will be a function of the seller/buyer relationship.

Will it just be for Indian diamantaires or will it provide a service for those in other centres as well? How would non-Indian businesses get goods to the facility and how will they get them back?

The testing service offered from the IIDGR Surat laboratory will be open only to the Indian industry. This will service the vast majority of melee which is in India. For the Belgian industry we will be running the same service on a smaller scale in Antwerp and for the Rest of the World from our UK laboratory in Maidenhead.

What referral rates will you use to confirm that a parcel is ‘clean’?

Our aim is to deliver a full testing service that includes screening and all testing of referrals

What will you do with any synthetics discovered through the referrals?

At this stage we anticipate that synthetics discovered through the screening and referral testing will not be provided with a certificate and will be returned to the customer in a tamper proof bag noting the synthetic origin. Customers will also be provided with documented guidance on proposed next steps which will support the WFDB charter. All cases will be fully confidential. Details are still to be finalised, however, and more information will be provided ahead of the launch of the service in October.

What will be the capacity of the service?

When the service begins operation in October it will be able to handle in excess of 13 million stones per year, with potential capacity building in excess of 13 million stones.

What is the expected turnaround time for the service?

This depends on size, volume and the number of referrals generated from initial screening which will require further testing. However, we aim to provide a very fast turnaround.

Why are you providing a service when so many Diamantaires own an AMS?

Our view is that it’s important for midstream participants to protect their business in every way possible and we see this as a complementary service to any in-house testing. Further to this, we are aiming to reach beyond those who own an AMS, to provide a level of assurance to the broader industry in places like Surat, India.

Is there potential to expand the service (in terms of both volumes in Surat and expanding to other locations)?

We have already expanded the service to both our Antwerp and Maidenhead laboratories.