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Diamond certificate

The diamond appraisal organizations that we handle are the three most trusted and well-established companies in Japan.

Gemological Institute of America (GIA)

The Gemological Institute of America (GIA), the world’s largest and most widely recognized non-profit gemmological research and education institution, developed the standards for the International Diamond Grading System™ (GIA Diamond Grading System). The GIA Diamond Grading Report is generally used as the global standard of diamond value.
GIA is the world’s most trusted name in diamond grading and gem identification. With objectivity and expertise as its hallmark of quality, GIA guarantees the accuracy and reliability of every report it publishes. GIA inspects all submitted material to determine whether it is natural and discloses any treatment detected during inspection.

GIA’s groundbreaking research, unbiased grading and analysis are the global standard for protecting gemstone buyers. With campuses, research centers, and laboratory facilities around the world, GIA is recognized as a global authority in gemmology.

Central Gem Laboratory Co., Ltd (CGL)

Central Gem Laboratory “CGL” is the largest appraisal institution in Japan with a reputation for reliability. The certificate is written in Japanese and in English and features an image of the diamond.
IT boast the largest market share in diamond appraisal and gem identification in Japan, and the number of diamond grading reports issued is one of the largest in the world, making it a standard presence in the Japanese jewelry industry.
When buying expensive jewelry, it is important that the jewelry looks good on you or if the price is right. The identification report analyzes and displays the type of gemstone and its authenticity, and applies to all gemstones. The grading report only targets diamonds and analyzes and displays the quality using the 4Cs. Prices are not displayed together.
Along with the diversification of natural gemstones, the advancement of synthesis technology is remarkable, and the identification and grading of gemstones requires a high level of specialized knowledge and experience. With this respect, the identification report and diamond grading report are the most effective ways to gain peace of mind, and they are a great clue in case of theft or loss.

Association of Gemmological Laboratories, Japan (AGT)

Established as a laboratory department of the Japan Gemological Association “AGT” as an agency of GIA. A gem appraisal and identification institution that boasts a history of supporting GIA JAPAN as a pioneer of gemological educational institutions in Japan.
From a strictly neutral and objective standpoint, with the aim of contributing to the protection and profit of the jewelry industry and consumers, the world’s most advanced gem identification equipment and GIA-G.G. has earned a great deal of trust.
DIAMOND GRADING
Diamond grading is to evaluate the quality of a diamond according to each standard of 4C (COLOR, CLARITY, CUT, CARAT). A “diamond grading report” is a report-style document that describes the evaluation and other detailed data and includes a photo of the diamond. At the AGT Gem Laboratory, two or more knowledgeable and experienced graders grade each diamond to ensure consistency of grade.

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