Josef C is a gemologist and purveyor of diamonds and jewels who is based in the NYC Diamond District.

A graduate of the Cornell School of Hotel Administration, Josef infuses hospitality into the diamond business, where he consistently exceeds client expectations. He gained extensive technical expertise by studying at the Gemological Institute of America (GIA) where he earned the Graduate Gemology degree (GIA GG), as well as the Accredited Jewelry Professional (AJP) and Graduate Pearls (GP) certificates. Additionally, he completed the diploma in Gemmology from the Gemmological Association of Great Britain (Gem-A), earning him the credential "Fellow of the Gemmological Association" (FGA); the FGA and GIA GG programs are the two most highly regarded gemological degrees in the world.

Josef previously worked as a diamond grader at the GIA Laboratory in Ramat Gan, Israel, after completing the industry's most intensive diamond training program; and developed a special eye for quality, detail and craftsmanship while working at Tiffany & Co. in New York City. A member of the National Association of Jewelry Appraisers (NAJA), Josef is  currently the only Certified Master Appraiser in New York.