Buying a diamond - Choice of certification

When buying from us, with both our website and the service offered we attempt to give the customer the facts on every aspect of the process so that they may make an informed decision on what is an important purchase.

All diamonds listed on our site are certified by one of four internationally recognised and trusted grading laboratories.


Established in 1931, the Gemological institute of America is an independent, nonprofit organisation employing a staff of more than 700.

With headquarters in the centre of New York City's diamond and jewellery district and a second state of the art laboratory in Carlsbad, California.

GIA created the famous '4 C's' that represent diamond value, cut, colour, clarity and carat weight. GIA's D-Z colour-grading scale and Flawless-I3 clarity grading scale are recognised globally throughout the jewellery trade, the institute is also known for having developed the first modern jeweller's loupe.

GIA Diamond Certification - Origins:

The Gemological Institute of America (GIA), founded in Los Angeles in 1931, is an independent, non-profit organisation considered by many to be the world's foremost authority in gemology. In 1953, the GIA created its International Diamond Grading System, which specifies uniform criteria for grading diamonds. The GIA grading system is recognised worldwide, and diamond manufacturers from around the globe send diamonds to the GIA's laboratories for examination and grading. Even the White House has trusted the GIA for answers to diamond-related questions. A GIA Diamond Grading Report is the most widely understood and trusted set of credentials that can accompany a diamond.


Triple redundancy: grade it, grade it, and grade it again. Two to five highly trained gemologists examine each diamond in the process of preparing a GIA Grading Report.

  • - Weight and measure are determined, and the stone's culet and girdle thickness are described.
  • - Colour is graded by comparing the diamond to master stones of predetermined colour.
  • - Clarity is assessed based on an examination of the stone under a binocular microscope of 10x magnification.
  • - Clarity characteristics are plotted on a diamond diagram.
  • - Polish and symmetry grades are assigned according to an inspection of the diamond's craftsmanship.

In some cases, additional, highly experienced gemologists review all the grading information and independently render their judgments of colour, clarity, polish, and symmetry. Grading results are finalised after a sufficient number of agreeing opinions have been rendered.

GIA certified diamonds - GIA cut grading on diamonds Cut Grade:

The GIA cut grade of a diamond is determined on an assessment of seven factors. The first four-polish, symmetry, weight ratio, and durability-refer to the make of the diamond. The remaining three-brightness, scintillation, and fire-describe the appearance of each brilliant round-cut diamond.

Example GIA certificate

GIA Gem Laboratory
580 Fifth Avenue, Suite 200
New York, New York 10036


Established in 1973 as the 'Hoge Raad voor Diamant' or the 'Diamond High Council', the organisation has nowadays become the major employer of the Antwerp diamond sector.


HRD officially represents the Belgian diamond sector at home and abroad. Established in Antwerp in 1973, HRD is a multifaceted organisation. Among its many departments are HRD Certificates, which meets the growing demand for diamond certifications, and HRD Research, which delivers technological support to the diamond industry. HRD is one of the world's most respected diamond institutes, and a great deal of pride is attached to each diamond that earns the HRD seal of approval.

HRD Diamond Certification - Methodology:

The HRD Certificates Department issues diamond quality reports based on international standards. To ensure that HRD diamond grading is completely fair and unbiased, the identities of diamond owners who submit stones for HRD certification are never revealed to the lab's gemologists. To further safeguard quality and consistency, senior gemologists randomly check grading results on a daily basis.

  • - Several gemologists analyse each diamond, assigning grades for weight, colour, clarity, and cut.
  • - The number of graders utilised increases relative to the size of the diamond.
  • - Each grader gives his quotation with no knowledge of other graders' judgments.
  • - A final grade is assigned only on the basis of a sufficient number of identical quotations.
Example HRD certificate

Hoveniersstraat 22
BE-2018 Antwerpen


IGI Headquarters are in Antwerp and were established there, they also have offices in New York, Hong Kong, Mumbai, Bangkok, Tokyo, Dubai, Toronto, Los Angeles, Tel Aviv and Cavalese, IGI is the world's largest independent gem certification and appraisal institute and is renowned for its quality services, extensive experience and know-how.

IGI, the oldest institute of its kind in Antwerp, was founded in 1975 and along with its sister laboratories is one of the leading gemological institutions worldwide.

Presently, a staff of just three has grown to over 450 professionals dedicated to a standard of excellence second to none and IGI issues more than one million reports per year.

IGI Diamond Certification - Origins:

The International Gemological Institute (IGI), established in 1975 in Antwerp and New York, is one of the world's leading gemological institutions. Thanks to the IGI's reputation for integrity, accuracy, and reliability, hundreds of thousands of diamonds pass through this laboratory's halls each year. In 1982, the IGI answered the growing demand for education, when it became the world's first gemological institute to offer courses in rough and polished diamonds. IGI has bases of operations in eight vital industry locations throughout the world.


Each diamond graded by the IGI is scientifically analszed by several graduate gemologists. These experts team their knowledge and experience with state-of-the-art equipment to prepare an accurate description of each diamond. All gemologists must agree on each diamond before a grading report can be issued.

  • - Weight is determined using an electronic balance that measures to ten-thousandth of a carat.
  • - Measurements are taken, and every angle and facet is measured to evaluate polish and symmetry.
  • - Clarity is graded by determining the number, nature, size, and position of any internal characteristics.
  • - this analysis is performed by means of a high-powered microscope and a 10x magnification loupe.
  • - Colour is described by comparing the diamond to a set of master stones of predetermined hue.

Example IGI certificate

IGI World head office
Schupstraat 1
2018 Antwerp


Founded in 1943, The American Gem Society (AGS) is dedicated to upholding the highest ethical standards in the diamond and jewellery industries. Professional and consumer education are AGS priorities, and the society offers courses to all segments of the diamond industry.

The AGS established a laboratory in 1996 to provide modern diamond grading services for the diamond marketplace. Its conservative approach to diamond grading has made the AGS one of the world's most respected gemological laboratories.

The AGS was the first diamond laboratory to issue a separate grade for diamond cut and to include that grade in each diamond report. Many laboratories have yet to catch up with innovations the AGS pioneered a decade ago.

AGS Diamond Quality Document and Report:

AGS uses a unique 0 to 10 grading system to quantify diamond colour, clarity, and cut. A grade of 0 indicates the rarest, most desirable quality; a 10 rating is the least desirable. Each number corresponds to the internationally accepted GIA diamond scale nomenclature.


Every AGS diamond certificate includes grades for colour, clarity, carat weight, and cut. One AGS laboratory gemologist grades the diamond and then passes it to another gemologist, who also grades the stone. The diamond is then returned to the AGS laboratory's support team, which enters the stone's specifications into a database and prepares a final report for the owner.

  • - Each diamond is weighed to the third decimal place by means of a digital carat balance.
  • - The stone is electronically measured to obtain millimetre size and proportions.A precise diagram of all proportions and angles is included in each diamond certificate.
  • - The diamond is tested for validity and enhancements, and shape and cut style are noted.
  • - Colour is determined by comparing the stone to master diamonds.
  • - Specialised lighting and a binocular microscope are used to determine clarity, which is plotted on a diamond diagram.

Cut Grade:

AGS considers the following factors when determining a diamond's cut grade:

  • - Light Performance (0-10 scale): A measure of the diamond's brightness and light dispersion as well as leakage of light and contrast.
  • - Proportion Factors (0-10 scale): Girdle thickness, size of culet, weight ratio, durability, and tilt are considered individually and then factored together to determine a final grade.
  • - Finish (0-10 scale): Finish is graded based on the diamond's polish (smoothness of facets) and symmetry (uniformity of diamond shape and facet placement).

Example AGS certificate

AGS Laboratory
Robert M. Shipley Building
8881 West Sahara Avenue
Las Vegas, Nevada 89117