Scott Kay, one of the most prominent and celebrated designers in the ­jewelry business, died of a heart attack on Dec. 4. He was 57.

He is survived by his three children and his wife of nearly 30 years, Regina.

His unexpected death comes at a time when his three-decade-old company was reinvigorating itself. It had hired a CEO and was beefing up its C-suite with an impressive roster of industry talent. Kay had moved up to chairman, hoping to concentrate on designing, and had hinted at other major announcements.

“I have big things cooking,” he told JCK this summer.

A nationally renowned jeweler often credited with resurrecting platinum, Kay grew up in Brooklyn, N.Y., the son of an alcoholic mother and absent father.

“I come from a broken home, and within that broken home there were tremendous difficulties,” he said in a biographical video. “You have a choice in life: You can either harbor on [that], or you can have this tenacity about the things that you want to do.”

An all-star athlete, Kay lacked post–high school ambition until, walking home from a catering job, he picked up a lug nut on the street and spent the next few hours molding it into a pinky ring. Then it hit him: This was fun. I can do this.

His next stop was the Fashion Institute of Technology. At least that was his plan. When his application received an unceremonious thumbs-down, Kay took a two-hour bus ride to FIT and barged into the office of the man who signed his rejection letter. Brandishing his homemade ring, he begged for a chance. The man finally agreed to let him take a summer class. “We’ll see if you have any talent,” he said. Kay’s time at FIT made him realize how committed he was to his craft: It was “a school that was 95 percent girls, and yet I focused only on jewelry design.”

Heaven’s Gates engagement rings; $2,410–$2,445; Scott Kay, Teaneck, N.J.; 800-487-2724; scottkay.com

He later helped his mother sober up and when she died, buried her with the ring that helped him get into FIT. “It was the most important thing in the world to me, but I wanted her to have it,” Kay said later.

In 1984, he opened his own design house and made his mark by embracing a little-used metal: platinum.

“I started looking for an identity in jewelry, something to be known by,” he told Florida’s Sun Sentinel. “I got to thinking, Platinum stands for the best of the best: platinum credit cards, platinum records. Why has it no presence in our industry?” Kay gave it one, and is generally credited with turning the formerly forgotten metal into a white-hot commodity. He later blazed similar trails by mixing bridal and fashion and, in a far-sighted move, bridal and branding. He prided himself on being an iconoclast in a staid industry.

“I don’t follow anybody,” he said. “When the world says hang a left, I’m hanging a right.”

Kay’s outspoken, sometimes swaggering persona—his company (and personal) motto was “never compromise”—stood in contrast to the delicacy of his art. His pieces were distinguished by an attention to often-minute detail as well as spiritual and religious themes.

His profile rose considerably when celebrities embraced his vision; his creations found their way to Gwyneth Paltrow, Heidi Klum, and Michael ­Jackson. Industry honors included designing the first De Beers Millennium diamond and being the first jewelry designer featured on the cover of Vogue Gioiello.

In July, he said he was working on a book about two things that meant a lot to him: faith and family. But his devotion to his craft burned as hot as ever. When asked what he would be doing if he wasn’t a jewelry designer, he replied, “Probably still walking around with that lug nut in my pocket.”