Mood rings sold $20 million worth of inventory in their first year on the market, according to HISTORY’s account of the 1975 launch. That number came from a single accessory, sold at a single New York department store, in a category that barely existed a season earlier. By the time the fad cooled, the man most people credit with inventing it had filed for bankruptcy, and a second man was still insisting the whole idea had been his first.

A Department Store Window and a Five-Million-Dollar Week

The mood ring debuted at Bonwit Teller in New York in 1975, credited to marketer Josh Reynolds and scientist Maris Ambats, per HISTORY. The pitch was simple and a little bit magic: a hollow glass or quartz stone filled with temperature-sensitive liquid crystal, worn against the skin, shifting color as body heat rose and fell. Blue meant calm. Black meant stressed. Nobody involved claimed it measured anything real, and nobody buying one seemed to care.

The rollout was fast in a way that’s hard to picture in a slower media era. Bonwit Teller told reporters it had booked $5 million in purchase orders in the first week alone, according to a profile of Reynolds published decades later in his hometown paper in Laguna Beach, California. There was no viral video, no influencer unboxing, no algorithm doing the pushing. There was a department store window, a novel bit of chemistry, and a public in 1975 that was primed for a little self-help mysticism wrapped in cheap costume jewelry.

Word of mouth did the rest. Within months, mood rings weren’t a department-store novelty anymore, they were a default gift, a stocking stuffer, a thing you bought a friend because it cost less than five dollars and came with a built-in conversation. Drugstores and mall kiosks picked up cheaper versions almost overnight, and by the 1975 holiday season the ring had fully escaped its original retail home and become a category unto itself.

Everyone Wanted Credit, Nobody Had a Patent

Here’s the part that makes the mood ring a stranger story than most 1970s fads: nobody actually locked down the invention. HISTORY notes that the origin “remains a topic of some debate,” pointing to designer Marvin Wernick, who separately claimed he’d been making color-changing jewelry with the same liquid-crystal technology before Reynolds and Ambats brought their version to market.

Without an enforceable patent anchoring the idea to one inventor, there was nothing stopping anyone with access to liquid crystal film and a jewelry mold from making their own version. And that’s exactly what happened. Knockoffs flooded in almost immediately, undercutting the original on price and quality, which meant the boom that made mood rings a household name also guaranteed nobody could fully own the payoff.

The technology itself wasn’t secret, either. Thermochromic liquid crystal had been used in scientific and industrial temperature displays for years before anyone thought to set it in a ring band. Reynolds and Ambats’ real innovation wasn’t the chemistry, it was the packaging: turning a lab material into a wearable mood indicator that felt personal, slightly mystical, and cheap enough for a teenager’s allowance. That kind of packaging insight is notoriously hard to protect legally, which is exactly why the credit fight never really got resolved.

The Fastest Fad Has the Fastest Fall

Two years after the $20 million debut, Reynolds filed for bankruptcy, per HISTORY. The math tells its own story: a market flooded with cheap imitators, a novelty that depended on being new, and a buying public that had already moved on to the next thing by 1977. Fads don’t usually die because people stop liking them. They die because the market gets crowded and the price collapses, and mood rings hit that wall about as fast as any accessory in memory.

Reynolds himself didn’t stay down for long, at least reputation-wise. He went on to develop other consumer products over his career, including the ThighMaster, according to the Laguna Beach profile, which makes him one of the rare people responsible for two distinct as-seen-on-TV-style crazes over the course of a single career. Bankruptcy, in his case, turned out to be a chapter rather than an ending, which is its own quiet lesson about the difference between a product failing and an inventor being finished.

What’s left of the mood ring today is mostly nostalgia and the occasional novelty shop reissue, but the underlying tension never really went away. A great fad idea moves fast enough that ownership becomes an afterthought, and by the time the money shows up, so does everyone else’s version of the same idea.