Platinum-leaf panels decorate the walls of The Breakers, Newport’s famous Gilded Age mansion.

The Preservation Society of Newport County photo

NEWPORT — For years, conservators at The Breakers were baffled by eight gleaming wall panels depicting muses of classical mythology. If the panels were made with silver leaf, why hadn’t they tarnished – even a little bit – in more than 100 years?

The answer has the owners of Newport’s most famous Gilded Age mansion, the Preservation Society of Newport County, downright giddy.

Architectural sleuths solved the mystery recently, thanks to the stubborn suspicions of museum experts and the assistance of a laboratory in Delaware. What they discovered was that the panels are covered with a far more valuable and precious material – platinum leaf.

“If America’s Gilded Age were to be represented by a single house, that house would be The Breakers, so for an important museum like ours, the discovery of platinum is the equivalent of striking architectural gold,” Trudy Coxe, CEO and executive director of society, said in a statement.

“Platinum was known to be difficult to work and decadently expensive, even back then. The fact that it was so beautifully incorporated in The Breakers underscores the wealth and power of the Vanderbilts, for whom money literally was no object. It also tells us that the world’s best architectural design firms were even more skilled and advanced than we had realized, or even suspected.”

In announcing the discovery this week, museum officials did not say how much the panels might be worth.

“It’s not something you can take off the wall,” said John G. Rodman, director of sales and marketing director for the preservation society.

While the mansion is probably irreplaceable, Fireman’s Fund Insurance Co. recently valued it for insurance purposes at about $350 million.

The Breakers was built in 1893 by iconic American architect Richard Morris Hunt for the family of Cornelius Vanderbilt II, president and chairman of the New York Central Railroad. Hunt assembled an international team of craftsmen and artisans to create the 70-room Renaissance-style mansion, inspired by 16th-century Italian palaces.

The Vanderbilts were known to have “spared no expense in the construction or decoration of The Breakers,” according to the society. The mansion boasts extensive gilding and marble features, a 50-foot high Great Hall, mosaic tile floors and ceilings, and expansive terraces with views of the ocean.

The eight panels are in each of the four corners of the Morning Room. Additional panels covered with platinum leaf are on the ceiling.

Recently, Breakers conservators, using non-invasive techniques, worked with experts from the Winterthur Museum analytical laboratory in Delaware to analyze the panels. The tests indicated the material was platinum.

“Because silver tarnishes so easily, we had suspected for decades that these Breakers’ wall coverings were crafted from a different material, probably tin or aluminum,” chief conservator Jeff Moore said in a statement. “Platinum never even occurred to us. I was speechless when we made the discovery.”