Since 1980, Guild Laboratories, in
Los Angeles, CA has been the most relied upon source for
securing expert gemstone grading, gem identification and independent
appraisal and valuation for diamonds, gemstones, jewelry and
Guild Laboratories president Charles Carmona, GG ASA has built
this reputation by delivering fair and impartial valuation reports
and consultation backed by decades of research and appraisal experience.
This thoroughly comprehensive manual does the difficult task of
estimating carat weights of mounted gemstones, calculated by their
dimensions and shape, with over 300 pages of tables listed, and
Guild Labs' President and Founder is often a featured
expert jewelry & coin appraiser in TV news shows and documentaries,
such as the Travel Channel. In the clip left, he discusses the
process for setting up the US Treasury Auction for jewelry and
Guild Laboratories is a trusted source for all of your gemological
With decades of experience, we provide the highest quality appraisal
services for diamonds and gemstones, jewelry, coins, and decorative
We offer consultation services, and provide experienced expert
witness and litigation support to private and governmental agencies.
See our SERVICES page to review our
complete schedule offered at Guild Laboratories.