Robert De Mario, of Italian descent, came to New York City as a child. After graduating from school, he began as an apprentice, and then as jeweler in local jewelry workshops. Having accumulated some initial capital, he founded his own company for manufacturing costume jewelry, importing, and retailing.

His company, Robert De Mario & Co., founded in the mid-1940s, was originally located at 392 Fifth Ave, New York City. Significant changes occurred in 1951, when the firm became a corporation with Robert De Mario as president. The company moved to larger premises at 435 Fifth Avenue, New York City, NY.

Frank P. DeMario

De Mario’s son, Frank P. DeMario, worked for his father’s company until 1951 while still a student at Brooklyn College. In June 1951, newspapers reported Frank DeMario’s engagement to Elvira De Rosa, daughter of renowned jeweler Ralph De Rosa and a partner in her late father’s company. Following their wedding in October 1951, Frank DeMario transferred to Ralph De Rosa Co.

One-of-a-kind jewelry

Robert De Mario crafted all his jewelry by hand, in limited quantities, and even one-of-a-kind. He used the finest materials—Murano glass beads, Swarovski crystals, imitation pearls, and gold-plated filigree. His jewelry is known for its rich use of color, unusual materials, and attention to detail.

Multi-strand necklaces, brooches, and rings adorning beautiful models regularly appeared in Vogue magazine in the 1950s and 1960s. Notably, the last advertisement in Vogue appeared in November 1966. Consequently, De Mario’s company operated until at least 1967.

Stanley Hagler

It’s important to note that in the 1960s, renowned designer Stanley Hagler collaborated with De Mario, creating many exquisite jewelry lines. Hagler had unique experience in jewelry design, having previously worked for the legendary Miriam Haskell. There are also suggestions that Robert De Mario also worked for Miriam Haskell, which is entirely possible.

De Mario himself lived a long life, dying at the age of 90, leaving his mark on the history of 20th-century costume jewelry. High quality and rare, De Mario jewelry has high collector value.

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