Ingrid Lederhaas-Okun, 46, was arrested on Tuesday at her home in Darien, Conn.
Prosecutors allege that Lederhaas-Okun used her position at Tiffany to borrow about 165 pieces of jewelry, including diamond bracelets, platinum or gold diamond drop and hoop earrings, platinum diamond rings, and platinum and diamond pendants, claiming she needed them for work reasons.
They say she then sold the items to an international dealer.
Authorities say Lederhaas-Okun left the company in February. The name of her attorney wasn't immediately available.
Tiffany representatives declined to comment Tuesday.