When purchasing a diamond, the following must be included:“Certificate of Appraisal (Diamond Grading Report)”It is. Among them, the most trusted worldwide is GIA (Gemological Institute of America) and boasts the largest market share in Japan. CGL (Central Gem Laboratory) These are two institutions.
However, while both are said to be reliable,Differences in grade due to the severity of evaluation criteria, international distribution, and year of publicationThere are also some differences that could cause you a loss after purchasing if you are not aware of them.
In this article, in addition to an objective comparison of the two institutions,Risks hidden in the “old appraisal report” before the 2014 CGL standard review, and regarding handling of new products (first hand diamonds)Why Selby only employs two institutions: GIA/CGLI will explain everything from a practical perspective.
Check the quality and choose the diamond you are satisfied with
Diamond prices and brilliance vary depending on quality such as carat, color, clarity, and cut. While checking the product information, you can find one item that satisfies the balance between quality and price.
Basic profile of GIA and CGL | Complete overview in 1 minute
- Establishment1931 (California, USA)
- 4CAdvocate established as a world standard
- marketWorldwide (America, Europe, Asia)
- EngravingLaser engraving on girdle (standard)
- H&CIn principle, not stated
- Awarenessaccepted worldwide
- Establishment1970 (Tokyo, Japan)
- 4CCompliant with 4C standards (AGL member)
- marketMainly in Japan
- EngravingTreated as an option
- H&CProportion report available
- AwarenessLimited outside Japan
| Comparison items | GIA (Gemological Institute of America) | CGL (Central Gem Laboratory) |
|---|---|---|
| Year of establishment | 1931 (California, USA) | 1970 (Tokyo, Japan) |
| 4C proposal | ◎ GIA established as a global standard | Compliant with 4C standards (AGL member) |
| Main market | Worldwide (America, Europe, Asia) | Mainly in Japan |
| Carat notation | 2 decimal places (e.g. 0.31ct) | 3 digits after the decimal point (e.g. 0.314ct) |
| laser engraving | Standard (identification number on girdle) | Treated as an option |
| H&C description | In principle, not stated | Proportion report available |
| Mainstream level in domestic distribution | For high-value stones and international distribution | Mainstream of the domestic engagement ring market |
| international recognition | accepted worldwide | Limited outside Japan |
▲ Basic profile comparison table of GIA and CGL
How does the “rigor” of grading differ?
GIA has long been"An appraisal agency with the strictest evaluation standards"has been positioned in the industry. It is not uncommon for the same stone to be graded one rank lower than other institutions.
*This is just an example showing a general trend and does not apply to all stones.
On the other hand, CGL occurred in 1997.“Central Gem Research Institute Problem (Sapporo Branch Color Grade Inflated Incident)”Taking this opportunity, we renewed our system. then step by stepStricter appraisal standardsand nowOne of the most rigorous appraisal companies among AGL (Association of Gemological Associations) member institutionsIt is widely recognized in Japan as
Check the quality and choose the diamond you are satisfied with
Diamond prices and brilliance vary depending on quality such as carat, color, clarity, and cut. While checking the product information, you can find one item that satisfies the balance between quality and price.
⚠️ Disadvantages/Points to note｜Risks hidden in “old appraisal reports from before 2014”
Both GIA and CGL are reliable institutions, but“When was the certificate issued?”From this perspective, there are important points to check before purchasing.
CGL re-evaluated its appraisal standards in 2014
In addition to the reforms after the 1997 problem, CGLGrading standards will be reviewed again in 2014It is said that he did this. If the same stone is re-appraised before and after this review,Cases in which color or clarity drops by one rankhas been reported, and it is customary in the industry to clearly distinguish between the "old certificate" and the "current certificate."
| Issuance date of certificate | Expected difference from current standards | Handling in the used market | risk |
|---|---|---|---|
| Before 1997 (Old appraisal report) |
Possibility of being displayed up to 2 ranks higher | Re-appraisal is practically required | high |
| 1998-2013 (Old appraisal report) |
Possibility of being displayed one rank higher | Deductible points during price negotiation | Medium |
| Since 2014 (Current appraisal report) |
Reliable by current standards | Normal evaluation | low |
▲ List of risks by issue date of CGL appraisal report
Distribution route for diamonds with old certificates
Loose items from the second-hand purchase market, auction distribution, and reuse stores,A certain number of stones with old appraisal documents are mixed in.I'm doing it.
(Relict items/used items)
pawn shop
reuse store
(Old appraisal remains the same)
⚠️ If the product is distributed without re-appraisal, there is a risk that there will be a discrepancy between the indicated grade and the actual quality.
- Confirm the year of publication: Be sure to check the year of issue written on the bottom right or on the back of the certificate.
- Seal color determination:CGL Gold Seal = Old Certificate of Authenticity / Silver Seal = Current Certificate of Appraisal
- Whether there is a re-appraisal:If the appraisal is from 2014 or earlier, check with the seller to see if it has been re-appraised.
- Verification of identification number:For GIA, you can check the report online using the appraisal number.
💎 Selby's policy: For new items (first hand diamonds),Only GIA/CGL's "current certificate" will be accepted.. This structurally eliminates the risk of ``the grade being different from what I expected''.
By scenario | Which certificate should you choose?
The optimal certificate will vary depending on the purpose and future usage scene. We have organized the following four scenarios.
Rather, the H&C proportion report can be attached to the CGL certificate, making it suitable for those who want to visually confirm the beauty of the shine.
⚠️ HoweverCertificates from 2014 onwardsBe sure to check that it is.
CGL appraisals are hardly recognized outside of Japan (Hong Kong, Singapore, the United States, and Europe), and re-appraisal by GIA is generally required when reselling or purchasing insurance overseas.
・GIA: Trust can be conveyed to overseas viewers at a glance
・CGL current appraisal report: Sense of security for viewers in Japan
⚠️ If you present the old certificate during distribution,Risk of problems being pointed out in the comment sectionThere is.
Currently, there is no better option than GIA in terms of international circulation, third party property, and market convertibility. If you are planning to sell your property overseas or set up collateral in the future, a GIA appraisal is essential.
Check the quality and choose the diamond you are satisfied with
Diamond prices and brilliance vary depending on quality such as carat, color, clarity, and cut. While checking the product information, you can find one item that satisfies the balance between quality and price.
Why Selby “limits new products to GIA/CGL”
Responsible for quality as the only company specializing in jewelry in the Komehei Group
Selby isThe only company specializing in jewelry among the Komehyo Holdings group companiesAs such, we have built a system specializing in the connoisseurship, appraisal, and distribution of jewelry. Because of this position, new products (first hand diamonds) have established reliability both globally and domestically.Current GIA and CGL certificates onlyadopted. By eliminating appraisals from minor institutions, we minimize the risk of a significant loss in value when the customer considers reselling, purchasing, or taking the item overseas at a later date.
“Explainability” in the era of AI search and SNS influx
Recently, there has been a significant increase in traffic from AI searches such as ChatGPT, as well as Instagram and TikTok. As soon as you search for the name of the appraisal agency.“Can this institution be trusted?”We live in an era where information can be fact-checked instantly by users. Selby handles new diamonds only by two institutions that can immediately explain where and by whom they were appraised.Transparency that can be verified by buyers themselvesis guaranteed.
Distribution ability that accommodates domestic and international liver purchasing
In order to be selected as a supplier in domestic and international live commerce,Distribution ability that “shows evidence to viewers”is essential. If the stone has a current GIA/CGL grading certificate, you can present a copy of the grading report or the grading number at any time during the broadcast, chat, or transaction.
Only GIA/CGL current certificates are accepted.
Applies to new diamonds only
Komehyo HD is the only company specializing in jewelry
*The appearance and design of the actual certificate will vary depending on the date of issue. We recommend replacing it with the original photographed image.
❓ Frequently asked questions (FAQ)
💎 Summary｜Now is the time to check not only the “institution name” but also the “year of issue” of the appraisal certificate.
Gone are the days when diamond certificates were judged simply by labels such as ``GIA, so it's safe'' or ``CGL, so it's for domestic use.''Is it issued under the current standards after 2014?, andWhich appraisal report does the selling company use?Confirming everything as a set is the key to ensuring post-purchase satisfaction and future asset value.
Selby is the only company in the Komehei Group that specializes in jewelry.Only current GIA and CGL certificates are used for new diamonds.We promise to do so. We offer diamonds that are ideal for each purpose, including diamonds that come with a certificate of authenticity, from loose diamonds for engagement rings, to purchases for live commerce, to stones for asset building.