GLASGOW — In a small, windowless room above Royal Exchange Square in Glasgow, Summera Shaheen has been customizing watches and creating jewelry for many of the world’s professional soccer players and their teams.

DaMarcus Beasley, an American defense player for the Houston Dynamo and the United States’ national soccer team, is in large part responsible for her speciality. The two met in 2007 at a charity event in Glasgow, and she ended up making a ring for him. “I was really into jewelry and diamonds,” said Mr. Beasley, who was playing in Scotland at the time. “We talked, and she made a pinkie ring for me with a princess-cut diamond. It was beautiful.

“I started taking my teammates to meet her. They like jewelry; they like watches; they like bling,” he continued. “I have played everywhere, so she has done work for my teammates from all different countries.”

In fact, Mr. Beasley has been such a big fan and steady customer, he has collaborated with Ms. Shaheen’s Diamond Studio business to create his own DaMarcus Collection of jewelry for men and women.

Jewelry has long been an interest for Ms. Shaheen, a Glasgow native — “It’s my passion,” she said. So after she completed a bachelor’s degree in politics and human resource management from the University of Strathclyde, she went to London to earn a certificate in diamond grading from the Gemological Institute of America.

In 2006, she returned to Glasgow and started her own jewelry business. “It’s difficult for a small independent brand to get the stock that bigger jewelers have,” she said. “So I did a lot of custom work.”

Last year, Ms. Shaheen began a service she saucily calls “Pimp My Watch.” She was designing custom wedding rings for a couple when the groom asked her to create a surprise for his bride: “He brought in a Rolex he had bought in America and asked me to add diamonds to it.”

Collaborating with a local man who has been working on watches for 25 years and getting cut stones from her usual sources, she created a bezel of white diamonds that can be added or removed from the watch, depending on how much dazzle is desired. “He gave it to her on their wedding day,” she said.

Soon, other customers wanted their watches to be blinged out, too. A recent customer was “going to start with having a diamond added to each number on the face and see how he likes it,” she said. “Then he might go for adding more diamonds to the bezel or case.”

Ms. Shaheen’s list of jewelry and watch clients from the soccer world is extensive, including Alan Martin, goalkeeper for the Scottish Premier League team Hamilton Academical; Maurice Edu, midfielder with the Philadephia Union and Team USA; Jozy Altidore, a forward for the Toronto Football Club and Team USA; Niall McGinn, a winger for the Aberdeen Football Club, another Scottish Premier League team, and the Northern Ireland national team; and Joe Ledley, a central midfielder with the English Premier League team Crystal Palace and the Welsh national team.

Mr. Martin, who recently consulted Ms. Shaheen about adding gems to a Rolex he owns, said, “I love the Diamond Studio because there is not any hassle with people trying to be in your face.”

“Summera takes her time and gives ideas on what you could do with the diamonds,” he said. “She takes pride in her business and puts everything into it.”

Ms. Shaheen also creates authorized jewelry collections for several soccer teams, something she says is a first. “No one has ever done quality official jewelry for sports associations before,” at least not complete ranges, she said.

And getting the agreements was not easy, she added. “It’s difficult for a female to be taken seriously, especially in the world of sports,” she said, “But because it was so hard, that made it exciting. If you see barriers, you just have to work harder.”

She uses a team’s official colors as the starting point for the jewelry, which includes rings, bracelets, pendants, money clips, earrings and card cases that Ms. Shaheen noted are “for holding your season tickets.” Some items are ready made, but everything can be customized in silver, 9-karat gold or even platinum. (Jewelry starts at 50 pounds, or $70, and customized pieces at £300.)

For example, white diamonds and red rubies can be used for Aberdeen team pieces, which have the team crest discreetly stamped on the back, or black and white diamonds for the Fulham Football Club, in the Football League Championship.

“It’s not like the usual sports jewelry,” she said. “It’s not hideous. And there’s something for female fans to buy, too.”

She also is the official jeweler for the Scotland national team and just signed a contract with the Northern Ireland national team. On her dream list: signing up Team USA.

Ms. Shaheen, however, always has her eye out for a new creation. Her latest is Diamond Dogs, a gold or silver tag studded with a small diamond and the dog’s name and, on the back, the owner’s name or whatever information is requested.

In December, when George Clooney was in Edinburgh at the Scottish Business Awards, the Scottish Chamber of Commerce presented one to the actor engraved for Millie, the basset hound that he and his wife adopted from a California shelter.

Mr. Martin, the Hamilton goalkeeper, has three dogs and is discussing getting tags for them all. And what does Ms. Shaheen plan to call the line in her business’s social media outreach? “Pimp My Dog,” she said with a laugh.