This autumn, Mr. Wellhoefer said, Swarovski will introduce a new crystal product, called a Concise Crystal, that is 50 percent lighter than previous stones, allowing for even more encrustation and refractory gleam.

“We’re in a crystal arms race,” Mr. Wellhoefer said.

The question now is whether we have reached the crystal saturation point when it comes to competition, or whether there is even further to go. “I ask myself that every tournament,” Ms. McKeown said. “We were doing a fitting with the girls the other day, and we all said, ‘Can you imagine what the leos are going to look like in four years if we keep going in this direction?’”

It may seem, given Ms. Karolyi’s coming retirement, that we are at a natural turning point in the sparkle situation. But if Ms. Biles and her teammates, all known crystalphiles, perform as expected while in full sparkle mode, chances are good that the millions of young fans who are watching will internalize the connection without ever entirely realizing why.

After all, when asked if there was ever a gymnast who tended, say, more to the minimalist Helmut Lang school of leotards than to the fairy princess Marchesa look, Jordyn Wieber, a member of the gold medal 2012 team who is now a student at U.C.L.A. and manager of the gymnastics team (which is known for the “creative backs” of their leotards), hemmed and hawed and thought for a while.

“Well, I guess some girls like more sparkle than others,” she offered, her voice trailing off. But, she added more decisively, “I have never met a gymnast who doesn’t love rhinestones.”