Maya metal ornament?

Ignacio Prieto writes: “10 years ago I bought an intriguing artefact online; it was described as ‘a metal ornament found in a cenote around Chichen Itza by the seller’s sister during a trip to Mexico years before’. It measures roughly 13 cm across, and has wear due to exposure. I am uncertain as to the type of metal employed, though I think it could be some sort of alloy? it is not particularly heavy, but it is ‘weighty’ none the less. It seems to have been plated with a shinier metal or maybe bleached with acids that I believe they used to use maybe in gold work?. The designs on the rings seem to resemble the hoops for the ball game the Mayans used to play - what I presume are intertwining serpents. Please help!”