Spotlight on July's Birthstone: Rosser Reeves Star Ruby Is the Largest and Finest in the World

July 2nd, 2014

Carried around for years as a good luck charm by 1950s TV advertising pioneer Rosser Reeves, the 138.72-carat gemstone that bears his name is the largest and finest star ruby the world has ever known Ruby is the official birthstone for the month of July.

Characterized by its rich red color and prominent six-rayed asterism, the cabochon-cut Rosser Reeves Star Ruby is now one of the most prized possessions of the Smithsonian National Museum of Natural History in Washington, DC.

Before donating it to the Smithsonian in 1965, Reeves called the stone “my baby” and made it his constant companion. The advertising executive, who penned the M&Ms slogan, “Melts in your mouth, not in your hand,” was one of the most successful admen of his day. And he attributed much of his good luck to the beautiful scarlet stone.

The famous ruby has an origin of Sri Lanka although it’s not clear when it was mined. According to published reports, gem dealer Robert Fisher purchased the stone at a London auction in 1953. At the time, it weighed 140 carats, but the asterism in the stone was slightly off center and the surface had abrasions. It was subsequently cut down to 138.72 carats to give it a prettier appearance and bring the “star” closer to the center. Reeves purchased the improved stone from Fisher’s son, Paul, in the late 1950s.

The ruby had been the subject of stories in the New York World-Telegram and The Sun as early as 1953.

The asterism is actually caused by titanium trapped in the corundum while the crystal is forming. As the crystal cools, the titanium orients itself as needle-like structures in three directions. A cabochon cut, with a smooth, rounded surface, allows the light to reflect off the titanium and give the appearance of a six-legged star.

Gem photos: Smithsonian Institution/Chip Clark.