Charles I. Carmona, coin appraiser and gemologist

About Gemologist Charles Carmona, President, Guild Labs


Charles Carmona

Guild Laboratories president and gemologist Charles Carmona has been a rock-hound and coin collector since the 1960s; eventually turning this passion into a gem and jewelry business. During the 1970s he was an importer of colored gemstones from Asia and South America.  He established Guild Laboratories in 1980.

Professional Affiliations

Mr. Carmona earned his Graduate Gemologist diploma from the Gemological Institute of America (GIA) in 1978 and was honored with the designation as GIA's ideal graduate in their global marketing campaign. His image and comments appear on GIA London's website. He has also taken numerous coin and currency courses given by the American Numismatic Association, (ANA).

Other specialized programs he completed include: American Society of Appraisers, Principles of Valuation Program at Lindenwood College, St. Charles, Missouri for Personal Property Valuation, Methodology, Research and Analysis; Report Writing; Appraisal Practice and Standards.

International Society of Appraisers, Certified Appraiser of Personal Property (CAPP) Program (Indiana University School of Continuing Studies), covering Appraisal Ethics & Business Practices; Appraisal Methodology, Markets & Formats; Appraiser & Law, IRS Report Writing; Advanced Appraisal Theory & Insurance.

International Experience

Mr. Carmona has performed appraisal assignments in 16 states in the US and its territories plus four foreign countries. Besides English, he is fluent in French, Spanish, and conversant in Portuguese.

This extensive experience has led Mr. Carmona to other key roles as an international appraisal expert.  He served as a gemological consultant to the World Bank as part of the program to establish the Institut de Gemmologie de Madagascar in Madagascar's capital, Antananarivo.

Mr. Carmona's other international appraisal work includes assignments in Mexico, China, Vietnam and Egypt.


Charles Carmona is author of The Complete Handbook for Gemstone Weight Estimation, found in many jewelry professionals' libraries.  It is the most comprehensive source for estimating mounted gemstone weights by using gemstone shape, measurements and specific gravity, and enjoys global popularity.

Staying On Top Developments

Staying current with gemstone and jewelry industry developments, he regularly attends regional, national and international trade shows, often as a speaker in their educational presentations.

Mr. Carmona travels to gem mining countries worldwideto gain first-hand experience in the gem trade by examining gemstones at their source.  As part of Guild Laboratories, He also hosts tours to foreign gemstone sites where tour members actually go into the mines and dig for gemstones.

Charles Carmona is a popular speaker for gem and mineral interest groups.

Gemstone Weight Estimation

Gemstone Weight Estimation Handbook

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 gemstone type.

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Charles Carmona is a leading authority in the gemological and gemstone field.

International agencies and individuals alike rely upon his expertise and trust his research backed valuation.

30 years experience as a certified gemologist and jewelry appraiser.
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