American Gemological Laboratories is a unit of Collectors Universe, the leading provider of value-added authentication and grading services for high-value collectibles and gemstones, which was founded in 1986 and publicly traded since 1999. In 1977, Ameri
The AGTA Gemological Testing Center is the natural coloured gemstone industry’s premier independent laboratory providing the industry and the public with a complete range of services, including gemstone identification, origin determination and pearl ide
Named after Russian Tsar Alexander II. A highly dichroic, rare variety of chrysoberyl. Emerald green in natural daylight, reddish in violet by artificial light, due to its unusual absorption properties. One of the hardest and most important gemstones. A f