Kaia Gerber, Addison Rae, Hailey Bieber, Emma Chamberlain—models, TikTokers, YouTubers, or some combination of the above, with tens of millions of followers—all own the same necklace. It’s a dainty cable chain, in sterling-silver or 14-karat-gold vermeil, with extra-puffy bubble-letter charms that spell out the owner’s name or initials.

In August, that Juicy Bubbles necklace was Rachel G Jewelry’s best-selling piece. It’s lucky that it’s also Rachel Gjersvik’s favorite piece to make because the 26-year-old behind the company sources, handcrafts, ships, and writes notes for everything she sells—by herself.

Rachel Gjersvik at work in her childhood bedroom, which doubles as her studio.

With a nine-to-five as a production assistant for a fine-jewelry line, this means waking up at sunrise to pour navy, green, butterscotch, and clear resin mixtures into 60 molds for the Retro Resin Cocktail Ring that Gjersvik designed during her freshman year of college; letting the resin cure in her window while she works her day job; heading to Manhattan’s Diamond District post-work to find chains for the bubble-letter necklaces, puka shells for her summer necklace collection, and Swarovski crystals to embed into her resin rings; and then sanding down the rings from two mornings ago in her studio—her childhood bedroom in her parents’ Upper East Side apartment.

“When my phone blows up with jewelry inquiries, people are like, ‘Hello, Rachel G team,’” Gjersvik says. “I’m like, ‘It’s just Rachel. Hello.’” This explains her drink order at our 7:30 P.M. interview in a hotel bar: black coffee.

Gjersvik started Rachel G in 2016 but has been making jewelry since she learned how to solder metal at summer camp. Later, her parents would take her to the Diamond District, in Midtown, to look at stones and meet chain salesmen. As an art student at the University of Michigan, Gjersvik designed pieces for class, sold chokers at a local Ann Arbor store, and, during summers, interned for designers she admired, such as Pamela Love and Kimberly McDonald. But jewelry was still a hobby, not a business.

Gjersvik’s pieces range from resin rings to namesake necklaces and pendants.

Then came the pop star King Princess. In 2018, Gjersvik took a postgrad gig at a P.R. firm just as a then 20-year-old King Princess—Mikaela Straus, for the people who know her—was preparing for her second headlining tour. King Princess wanted merch—not just cheap T-shirts and tote bags but accessories her fans would actually like to wear. A mutual friend introduced her to Gjersvik, and, with just a few guiding words from the singer—such as “69” and “weed”—Gjersvik designed her first collection, which debuted a year later.

Gjersvik thought the four-piece collection, which included a 69 Dice pinky ring and a chain with a small but detailed bong charm, would be a modest hit—she envisioned maybe 30 orders the first day. Instead, so many people tried to buy the line on launch day that King Princess’s Web site crashed. “I was booking it to 47th Street,” Gjersvik says.

The success of the collection inspired Gjersvik to quit her day job and focus exclusively on her jewelry for a few months. “I was like, I’m gonna give this my all, and if it doesn’t work, it doesn’t work.”

While making and shipping out the King Princess collection, Gjersvik teamed up with the model turned singer Cailin Russo for a one-piece collection—a silver necklace with a double-sided drama-mask pendant. Another singer with hundreds of thousands of followers posting and tagging Rachel G Jewelry in Instagrams meant more and more orders. As the sole member of the Rachel G press team, Gjersvik looked for more influencers, models, and singers who might like her “minimalist yet funky” designs, and sent them custom rings and necklaces.

The Rachel G Puka necklace, with customized initials.

“There’s no nagging from me,” she says. “If they like it, they will wear it.” And if they wear it, that means they post it online.

This summer, just three years after the first collection, Kaia Gerber wore the Rachel G Retro Cocktail Ring in the June/July issue of Vogue—the only piece on Gerber with a double-digit price tag. Being featured in Vogue means even more attention and orders, but Gjersvik intends to keep Rachel G a company of one. “I get to touch every piece I ship out,” she says. “That’s what is fueling me and getting me amped to create more.”

Gjersvik sells her jewelry exclusively on her Web site, and every time someone purchases a piece, an app on her phone dings. When her family meets in the living room at night to watch The Real Housewives and hears that ding, they look over to Gjersvik, who then heads to her childhood bedroom to prepare the order.

Jensen Davis is an Associate Editor for Air Mail