Guild Gem Lab, based in Los Angeles, CA, USA, was established by the renowned American gemologist Mr. Charles Carmona in 1980. Guild owns rich experience, refined database and solid research in areas of gemstone identification, grading and geographic origin determination. Guild now can be found in Los Angeles, Hong Kong and Shenzhen.
Since 1980, Guild has been focusing on testing colored gemstones, especially on treatment detection, origin determination and color grading of emeralds, rubies, sapphires and more.
The principle of Guild Gem Laboratories is to “provide clients with professional and trustworthy services”, to ensure the integrity, trust as well as accuracy of gem testing.
By applying highly efficient work procedures and ensuring the premium quality of testing, it normally takes 7 workdays to finish the job, which save much valuable time for our customers, compared with the general testing duration of 1-2 months elsewhere.