NEWPORT, R.I. -- For all its opulence, The Breakers mansion in Newport was never known to be immune to the laws of nature. That's why conservators could never explain why eight silver leaf wall panels there hadn't tarnished even slightly in more than 100 years.

That mystery was solved with the help of museum officials and a Delaware lab that discovered the silver leaf panels weren't silver at all, but rather the far more precious platinum leaf.

The discovery, announced this week, stunned chief Breakers conservator Jeff Moore, The Providence Journal reported.

Moore said conservators long suspected the panels -- which depict muses of classical mythology -- weren't silver, but thought they might be tin or aluminum.

"Platinum never even occurred to us," Moore said in a statement. "I was speechless when we made the discovery."

Breakers conservators, using non-invasive techniques, worked with experts from the Winterthur Museum analytical laboratory in Delaware to analyze the panels. The Preservation Society of Newport County said the discovery was "the equivalent of striking architectural gold."

"Platinum was known to be difficult to work and decadently expensive, even back then," Trudy Coxe, CEO and executive director of the society, said in a statement. "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."

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

Fireman's Fund Insurance Co. recently valued the mansion at about $350 million.

© Copyright 2006 Globe Newspaper Company.