Diamond certification is the process of examining a diamond and reporting upon its characteristics according to standards set by the grading laboratory. A diamonds certification enables a buyer to understand the quality of a diamond objectively without needing a great deal of expertise. There are several major diamond grading organisations whose reports are commonly seen associated with loose diamonds and diamond jewellery in the UK. The International Gemological Institute (IGI) is one of the best-known grading laboratories in the world and in terms of the number of diamonds graded are probably the largest grading organisation in the world. In terms of reputation, IGI is perhaps second only to the GIA (Gemological Institute of America) and is well-known in the United Kingdom.

About IGI

The IGI was founded in 1975 in Antwerp, Belgium. The company has branches in many countries, but not the UK.The company is well represented in Asia, particularly India, where most of the world's diamonds are cut and polished.

IGI is highly reputed for their speedy reporting and low cost, making them a favourite with low to mid-cost volume jewellers.

Although the company has almost 500 staff working across its international network, the company claims it maintains strict control of standards.

Services offered by IGI go further than diamond grading and reporting and include laser inscription of identification marks, table branding, diamond repair, jewellery engraving, and photography. The company also offers gemmology training in their own schools and via distance learning.

IGI Grading Standards

For diamond buyers, consistency between different grading organisations and within the same organisation's different branches is essential. Buyers want to be able to compare diamonds and diamond jewellery from various outlets before making their buyingdecision. If standards vary significantly, then a comparison of quality and value become very difficult. In this, GIA has the foremost reputation.

IGI has some structural issues that make it possible for diamond dealers to game their system and make comparisons harder.

1. It seems that some branches, notably in India, tend to rate diamonds that they assess somewhat higher than otherIGI branches; for example, in the USA. Diamond dealers knowing this can choose where their diamonds will be certificated.
2. Even though some branches have similar grading standards to the gold standard GIA, they allow recertification of diamonds previously certified in other offices. When they do this, they seem to follow the grading of the first branch and simply issue a new grading certificate with the new branch details. This means a more laxly graded diamond will have the seal of approval of the supposedly more stringent branch.

Although these issues have been rumoured, surveys carried out support these concerns. Diamonds have sent for certification by both IGI and GIA with the IGI certifications being higher than for GIA. Similarly, when gems are graded by differencing IGI labs, there is an inconsistency between the IGI labs. The issue of honouring grades from other branches has similarly been demonstrated in practice by sending diamonds for re-certification.

Grading Consistency And Diamond Values

Diamond grading reports are not an estimate of value or an appraisal of value, and the certificates carry no indication of the cost of a diamond. Jewellers use the grading certificate to justify the selling prices of diamonds in both loose form and mounted in jewellery. Even a single grade difference in quality will have a significant effect on the retail price of the diamond. The buyer has no practical way to determine the accuracy of the grading. Buyers can only trust that the classification is both accurate and consistent with diamonds graded by other labs, or by the same company at different branches.

Diamond vendors know how different grading labs operate. They choose the most profitable lab; usually, that means the one that will offer the highest grades for any given type of diamond.

What Does Grading Inflation Mean To Buyers, In Practice?

Some diamond experts suggest that IGI grades might differ from GIA grades by as much as 2-4 ratings. A GIA graded diamond might have an I colour grade from GIA but be ranked as a much more valuable G colour when graded by IGI.

A jeweller may offer his IGI G graded diamond at a lower price than a competitor's GIA graded G colour diamond and claim that his diamond a great deal. It isn't! The two diamonds are not actually comparable in quality. The more expensive GIA graded diamond will be a better-quality diamond, at a higher price. The GIA diamond is likely to be a better buy because the buyer will be getting what he paid for!

The best practice for diamond buyers is to seek out diamonds certified by a diamond grading lab known for its consistency and accuracy.