Pearl Certification Guide: Hanadama, Tenyo, PSL & What They Actually Mean

Intro

In the world of pearls, certification has emerged as one of the aspects of the secondary market. Its significance in China is central where trust issues between consumers and retailers exist. In response, Japanese laboratories began providing certificates of authenticity and quality, which helped to partially alleviate the problem. In this article, we will dive into the intricacies of pearl certification, what these certificates signify, and the laboratories responsible for producing them. With a focus on Akoya pearls, we'll explore the key aspects of certification that you should be aware of.

What is pearl certification (certification vs grading)?

In simple terms, pearl certification involves the issuance of documents by a laboratory to authenticate the pearls. This is achieved through various tests, including an X-ray test to determine whether the pearl is nucleated — the same radiography approach the GIA uses to analyze pearls. The laboratory charges a fee for this service, which can be performed by any lab qualified to certify pearls.

With time, laboratories have developed their own grading systems to further differentiate pearl quality. For instance, Japanese Akoya pearls are graded using systems such as TENYO (which means angel), HANADAMA (which means flower-pearl), and ROSÉ, which are based on factors such as nacre thickness, smoothness of the surface, and luster — the same dimensions captured in the internationally recognized GIA 7 Pearl Value Factors (size, shape, color, luster, surface, nacre, and matching). These grading systems provide a means for consumers to make informed decisions about their pearl purchases based on the quality and value of the pearls they are acquiring.

Who certifies pearls?

Pearl certification can be provided by any lab that is equipped to do so. In Japan, some of the better-known labs are PSL (Pearl Science Laboratory) and the Pearl Institute. Trained testers receive the pearls and certify them. Upon the sender's request, the lab charges a fee to test the item's quality and determine if it can be graded.

The criteria for a pearl to pass the grading process are somewhat obscure. This leaves many pearl professionals puzzled as to why certain pearl passed grading while others did not.

Pearl grading vs diamond grading

Nowadays, diamonds are a commodity that is traded using a price list distributed amongst wholesalers. There is very little room for negotiations amongst professionals, and the grading heavily relies on computer technology. These are two major differences between pearls and diamonds.

Pearls have not gone through such a process and are traded as they have been for centuries. Two professionals meet and negotiate based on each party's views of the item at hand. In addition, pearl grading heavily relies on the human eye, which is not as consistent as computers and technology used for grading diamonds.

Pearl grading consistency issues

As mentioned, the nature of pearl testing leads to many consistency issues, which can be better explained through the following examples:

1. Results may vary depending on the pearl tester. This creates a range of qualities even within a grading tier. For example, you may find Japanese Akoya Hanadama strands that are not as nice as others.
2. Occasionally, a product that didn't pass the test could be re-sent and receive a positive result the second time.
3. Different labs have different standards. This means that Hanadama grading from Lab A may not be as strict as that from Lab B — one reason the World Jewellery Confederation publishes the CIBJO Pearl Blue Book, the globally accepted reference for pearl nomenclature and classification.

Standardization is slowly improving across the industry — in 2025, GIA rolled out a five-range nacre scale across all its pearl classification reports. Later on, we will discuss the impact that labs, as private businesses, have on the pearl world.

Benefits and risks of purchasing certified pearls

Benefits

• Many people are unfamiliar with saltwater pearls and cannot assess their authenticity or quality on their own. Third parties can help increase confidence during the purchase.
• Certification can remove trust issues towards the seller, but this should be taken with a grain of salt. Untrustworthy sellers have been known to send the same strands for grading and sell certificates with lesser quality strands.

Risks

• A graded item, such as Hanadama, could cause the seller to increase its price by at least 50~75% over what it would have been without a grade, due to an increase of the end customer's willingness to pay.
• As mentioned earlier, there are many inconsistencies in results. This can lower the trust professionals have in the labs. In other words, even if a strand is graded, it might not be as beautiful as a non-graded strand. This means that you could be paying a premium for a lesser item.

Pearl laboratories are a private business

In the past, the Japanese government managed pearl inspection to control the quality of exports. However, there is no longer any regulation of the pearl quality being exported. This has led private labs to enter this space as a business, with the primary goal of generating profit.

As a result, labs try to generate as many tests and certificate prints as possible. They may even mention that an item almost passed, and mark pearls to be replaced in order to receive a grading. This encourages companies to resend items for testing.

Furthermore, labs may favor companies that send pearls for certification and grading on a regular basis. They may even reward this recurring revenue by providing a certain percentage of passed tests.

As with anything, this secondary market is not immune to politics, and one could argue that they have an impact on grading test results.

Conclusion

The creation of pearl certificates was a response to a lack of consumer knowledge and trust regarding pearls. In this article, we distinguished between certification and grading, and discussed their consistency.

We also examined how the lab's status as a private business can impact grading. The main takeaway is to educate oneself about pearls and to seek out a reputable pearl vendor who is willing to educate and assist in the process of finding the perfect pearl, rather than relying solely on certification.