Gem Report - UGL Japan

The Universal Gem Laboratory (UGL), known in Japanese as Kabushiki Gaisha Universal Gem Laboratory (株式会社ユニバーサル ジェム ラボラトリー), is a long-standing, specialist gemological laboratory based in the heart of Tokyo’s jewelry district, Ueno (Okachimachi).  UGL laboratory was established in 1983 by Masahiro Yamada, a highly respected figure in Japanese gemology. Yamada was a pioneer in bringing international standards to Japan, having earned his Graduate Gemologist (GG) title from the GIA (Gemological Institute of America) in 1974, followed by a Fellowship (FGA) from the Gemmological Association of Great Britain in 1976.

Unlike larger international labs, UGL is a boutique Japanese institution deeply embedded in the local trade, known for its technical precision and adherence to strict Japanese grading standards. Located in Ueno (Okachimachi), Tokyo’s "Jewelry Town," UGL was positioned to serve the high-volume diamond and colored stone wholesalers that define the Japanese market 

UGL is particularly valued by collectors and designers for several specific services:

• "Pigeon Blood" and "Royal Blue" Certification: In 2021, UGL officially began issuing specific color trade-name certifications (like Pigeon Blood for Rubies and Royal Blue for Sapphires) based on the strict standards of the Association of Gemmological Laboratories (AGL) Japan.

• Conservative Diamond Grading: Within the Japanese market, UGL is known for "strict" grading, meaning their diamond certificates are highly trusted by domestic retailers who want to ensure they are not over-grading their stones.

• Card-Sized Certificates: UGL was an early adopter of the "Card Identification" format—a compact, credit-card-sized plastic certificate that is easier for designers and retailers to include in jewelry boxes than traditional large paper reports.