“The Sunrise Ruby” sold at Sotheby’s Geneva for more than $30 million.

WHAT: Called “The Sunrise Ruby,” the cushion-cut stone of almost 26 carats set between two shield-shaped diamonds of almost three carats each brought $30.3 million at Sotheby’s Geneva this month, breaking the world auction record for the gem.

MORE: Made, signed and numbered by Cartier, the ring has French assay and maker’s marks. A gemologist’s grading certifies that the stone is of Burmese origin, has not been altered and has a rare and desirable color. (Pigeon’s blood is a deep, rich tone.)

SMART COLLECTORS KNOW: All rubies are not equal. The Sunrise Ruby is an unadulterated stone as found in nature.

HOT TIP: The only thing that most rubies sold today share with this natural stone is mineral composition. All else, such as color by heating, is enhanced.

BOTTOM LINE: The ring brought $30.3 million because the unusually large stone has been certified as 100 percent natural. Such stones do not often come to sale. The best rubies came from Burma, and those mines are now closed. The ruby’s desirable color and the setting’s assay marks from the Paris location of a prestigious jeweler make it priceless.