I've read some accounts from conquistadors who described some Incan objects that were apparently never captured by the Spanish. One was the "Golden Chain of Huascar" which was supposed to be a couple of hundred feet long and made from gold (otherwise I suppose it would have been called the "silver chain of Huascar"). This chain was said to have been hidden in the bottom of a lake to keep it from Huascar's brother, Atahualpa, during their power struggle.
Some of the buildings in Cuzco were said to be clad in silver and gold foil, before the Spaniards stripped it all off. Must have been quite a sight.
PrecolumBling!