Her death was announced in a joint statement from her company and the Nando and Elsa Peretti Foundation. She died of natural causes.

When Ms. Peretti moved to Barcelona to become a model in the mid-1960s, her wealthy Italian family cut off financial support. She became part of an artistic enclave that included surrealist artist Salvador Dalí before moving to New York in 1968.

“I arrived with a black eye, from my lover, who didn’t want me to go,” she later recalled to Vanity Fair.

With her tall, elegant appearance, she became a favorite model of designers, including Issey Miyake, Charles James and especially Halston, who went by just one name.

“Elsa was different from the other models,” Halston once said. “The others were clothes racks — you’d make them up, fix their hair, and then they’d put their blue jeans back on. But Elsa had style: She made the dress she was modeling her own.”

While working as a model in New York, Ms. Peretti began to design accessory items, including belts and a tiny silver bud vase worn as pendant on a chain or leather strap. (The vase was functional and could hold a small flower.)

Inspired in part by Halston’s minimalist style, she became a designer for Tiffany & Co. in 1974. She also designed a perfume bottle for Halston, with a rounded teardrop shape.

Ms. Peretti and Halston became close friends and were often seen together at New York discotheques in the 1970s, including Studio 54. During those years, Ms. Peretti admitted to subsisting on little more than caviar, cocaine, vodka and cigarettes. She was fluent in English, Italian, Spanish and French and often mixed all four during a conversation.

Strong-willed and tempestuous, she had a fiery temper that she sometimes turned on Halston, despite their close relationship. He had given her a sable coat for designing the perfume bottle, but after an especially heated argument, she threw the coat in a fireplace, where it was immediately consumed by flames. They reconciled before Halston’s death in 1990.

By then, Ms. Peretti was already celebrated for her jewelry designs. Instead of gold, she turned to silver as her primary metal, preferring its stark clarity and relative affordability. She often based her ideas on simple shapes found in nature, such as beans, scorpions and snakes.

Ms. Peretti traveled the world to find skilled jewelry makers and held each item in her hand, testing its contours and heft, as if it were a living thing. One of her earliest designs was a necklace shaped exactly like a kidney bean but made in silver or gold. She later incorporated the bean design into countless other items, from cuff links to purses.

She designed earrings shaped like teardrops and used finely woven gold and silver mesh to create a feathery metallic scarf that could be draped or tied. One necklace design, on closer examination, was a metallic representation of the curving skeleton of a snake.

“Good line and good form are timeless,” Ms. Peretti told the Wall Street Journal last year, adding, “I want my designs to be clear, simple but sublime.”

One of her most familiar designs was the “bone cuff,” a wide metal band worn as a bracelet. It included a noticeable protuberance in the metal, allowing it to fit comfortably over the wrist bone. Ms. Peretti got the idea from handling bones, which she sometimes stole as a child from underground crypts in Rome.

“Things that are forbidden remain with you forever,” she said.

She also developed the concept of diamonds and pearls “by the yard,” placing them widely on a necklace to keep prices lower. One of her most popular designs, the “open heart” necklace, is a heart-shaped frame of silver, with a chain through the empty center.

Over the years, Ms. Peretti maintained tight control over the design and manufacture of her items, which came to include tableware, drinking glasses and leather goods.

In 2019, Tiffany estimated that its stores around the world sold an object designed by Ms. Peretti once every minute. Items with her “open heart” design were sold once every three minutes. (Last year, Tiffany was bought by LVMH Moët Hennessy Louis Vuitton for about $16 billion.)

“The day Elsa Peretti became a part of Tiffany & Co. was the day we entered a new era in our history of design innovation,” company chairman William R. Chaney said in 2001. She “not only created a model for style and elegance that defined contemporary life, she changed forever the way people think about jewelry and incorporating fine taste in their lives.”

In 2012, Ms. Peretti announced that she was planning to retire. At the time, her designs accounted for 10 percent of Tiffany’s annual sales of about $3.8 billion. When the company offered to buy her name, designs and intellectual property, she balked. Instead, she negotiated a new 20-year contract, in which she retained control of her line of products. She received an outright payment of more than $47 million, plus an additional $450,000 a year and a 5 percent royalty on net sales of her designs.

“It was my price for the past,” Ms. Peretti told Vanity Fair about the contract, which remains in force after her death. “It might look like a lot, but, after taxes, it’s not really, for the work I’ve done.”

Elsa Peretti was born May 1, 1940, in Florence and grew up in Rome. Her father was the founder of an oil company; her mother did not work outside the home.

She was educated in Rome and Switzerland and was a ski instructor and French teacher before moving to Barcelona.

When Ms. Peretti was featured in a 1977 cover story in Newsweek magazine, her father finally took pride in her accomplishments — and died months later. Ms. Peretti inherited 44.25 percent of the shares of her father’s company. Her older sister, Mila, her only sibling, received 55.75 percent.

Ms. Peretti sued her sister and brother-in-law, seeking to obtain an equal stake in the company. Her percentage of the stock was raised to 49 percent through arbitration. Afterward, Ms. Peretti demanded that her sister and brother-in-law buy her out. The rift between the sisters never healed. Ms. Peretti received hundreds of millions of dollars, which she used to establish a charitable foundation named after her father and herself.

Ms. Peretti never married but had numerous relationships with men, including photographer Helmut Newton. Her longest relationship was with an Italian contractor, Stefano Magini. Their first encounter was an animated argument after he knocked down a gate at her home with his truck.

“We were together 23 years,” Ms. Peretti told Vanity Fair in 2014. “Ten were great.”

Through the years, she had homes in New York, Barcelona, Rome and Porto Ercole, Italy. Her primary residence, however, was in Sant Martí Vell, Spain, a medieval village outside Barcelona, where she bought a house in 1968.

“My first years,” Ms. Peretti told Vanity Fair, “things were still in ruins, many of the houses didn’t have roofs, and I slept on a bench and washed myself on the stone floor.”

She restored many buildings throughout the town, planted a vineyard, launched a wine label and stayed in close touch with the Barcelona metalworkers who executed her jewelry designs.

“I didn’t want to become someone,” she said of her retreat from the limelight. “I wanted to do what I wanted, to work with artisans, with my people. They bring my fantasies to life.”