Pennsylvania Ballet principal dancer Amy Aldridge's favorite ballet is "Rubies." Off stage, she prefers to work with diamonds -- she's enrolled in a gemology program with the Gemological Institute of America.

Aldridge's final turn on stage will be in May, dancing the "Rubies" pas de deux from George Balanchine's Jewels, the ballet announced Tuesday. After she retires, she plans teach ballet and finish up her diamond studies.

"It's going to be a huge transition because I've been doing this my whole life. It's what I know," said Aldridge, who has danced with the Pennsylvania Ballet her entire 23-season career.

Still, "I'm so excited," she said. "I want to take some of the pressure off myself, have some more freedom to do some other things, pass on my knowledge, not be the one under the microscope."

As a principal dancer since 2001, Aldridge has been a beloved performer, known for being able to leap into various roles, and particularly for her work in Balanchine ballets, modern works, and full-length classics.

She performed major roles in Cinderella, A Midsummer Night's Dream, Sleeping Beauty, Theme and Variations, The Taming of the Shrew, La Fille mal Gardée, Square Dance, Slaughter on Tenth Avenue, Ballo della Regina, Petite Mort, George Balanchine's The Nutcracker, and many others.

A reliable, calm presence on stage, she was also chosen to dance Tarantella in the New York City Ballet's Balanchine Celebration in 2004,  when dancers from various Balanchine-oriented companies were invited to perform.

Aldridge, from Richmond, Va., started dancing at age 5 and was a competitive swimmer until adolescence, when she had to make a choice. "I obviously couldn't do both. Breast stroke was my stroke, and swimming tends to make the women pretty broad. I still miss swimming."

She went to high school at the North Carolina School of the Arts, then joined the Pennsylvania Ballet right out of school. Now, she is looking to return to her education.

Along with studying diamonds, with an eye toward designing jewelry, Aldridge  plans to pursue a bachelor's degree. She will start at Community College of Philadelphia and hopes to transfer to the University of Pennsylvania or Drexel University. She also plans to stay connected to the ballet world as a teacher.

Her career goal as a dancer had always been to dance for 22 seasons. "I went one year longer than I thought I would," she said. "I've been thinking about it for the last two to three years  -- when was the right time and the right program?

"The end of last year, when we got the list of this year's season," and the "Rubies" pas de deux was planned, "I just knew. Mentally, I was in a good place," she said. "I feel fortunate that I've been given the OK to finish when I wanted to finish and with what I wanted to finish."

Aldridge last performed "Rubies" in 2013, when the Pennsylvania Ballet danced Jewels for the company's 50th anniversary.

"It was some of the best dancing I've ever done in my career," she said. "It has everything I do well: petite allegro, personality. Of everything I danced, that's my favorite."

Before retiring, Aldridge had also wanted to dance the principal role in one last full-length ballet, which she got to do this month in Le Corsaire.

"It was probably the hardest full-length I've ever done, definitely a treat and a challenge."

Other highlights of her career include European tours and special gigs -- filling a corps de ballet spot with the New York City Ballet when it performed "Rubies" in London, dancing with choreographer Kevin O'Day in Germany, performing former Pennsylvania Ballet artistic director Christopher D'Amboise's works in Portugal.

She said also cherishes having worked with choreographers like Dwight Rhoden, Alonzo King, and William Forsythe (twice).

Of working with Forsythe, she said, "I imagine it's what it would've been like working with Balanchine ... He was so wise, so nurturing. I feel like I learned a lot about myself."