Cos Altobelli, ECGA
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Cos AltobelliCos Altobelli, ECGA, is a third generation jeweler and president of Altobelli Jewelers in Burbank, California. In 1969, Cos earned a graduate gemologist diploma from the Gemological Institute of America as well as Certified Gemologist® title from the American Gem Society. He has been the Appraisals Committee Chair for over 25 years.

Cos organized the first formal appraisal education program in the United States, the Certified Gemologist® Appraiser for the American Gem Society. He has appeared on "Prime Time Live" assisting in exposés on diamonds, synthetic stones, and pearls. His appraisal expertise has been required at museums, legal and financial firms, and government agencies. He has written three appraisal books and donated hundreds of hours to the service of the AGS. The Cos Altobelli Library was named after Cos to honor his contributions to the Society.


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Mission Statement

The American Gem Society (AGS) is a nonprofit trade association of fine jewelry professionals dedicated to setting, maintaining and promoting the highest standards of ethical conduct and professional behavior through education, accreditation, recertification of its membership, gemological standards, and gemological research.

The Society is committed to providing educational products to inform and protect the consumer and to contributing to the betterment of the trade by creating industry standards to protect the jewelry-buying public and the fine jewelry industry as a whole.

AGS Laboratories, founded to support the AGS mission, is a nonprofit diamond grading laboratory with a mission of consumer protection. Adhering to the AGS Diamond Grading Standards, AGS Laboratories is dedicated to offering diamond grading reports that provide consistency and accuracy based on science.

American Gem Society

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