A$AP Ferg attends the Tiffany & Co. Paper Flowers event and Believe In Dreams campaign launch on May 3, 2018 in New York City.

When ASAP Ferg was still a teenager in the Hamilton Heights neighborhood of Harlem, he started making crystal-studded pendants. He would sketch designs of characters like Bart Simpson and Mega Man, then hand the drawings over to Earl Harley (also known as "Harley, the buckle man"). Mr. Harley would create the bases for Ferg, who would then add Swarovski crystals and sell the pendants. They cost him about $200 to make; he sold them for about $700 a piece.

A decade later, Ferg, born Darold Ferguson Jr., is hawking pricier gems. This month, he became the first male rapper to appear as a spokesman for Tiffany & Co., the luxury jeweler. Ferg, 29, is not yet a megastar nor the most famous artist in the ASAP crew (that would be Rocky). But in collaborating with him, Tiffany has aligned itself with a princeling of Harlem fashion who aims to honor the legacy of his father, the designer Darold Ferguson Sr., by out-accomplishing him.