The Decayed Brooch of Nguyen Visconti is a 517 years old piece made by Nguyen Visconti, a bailiff living in Ulaanbaatar.
Considering its age and the quality of the work, people consider it of no value.
It is engraved with asian patterns and some symbols pertaining to Jainism.
This piece doesn't exist, but as a legend. It is said that in the year 1617, Banyong Visconti, the owner, made use of it in Ulaanbaatar to empower the Visconti family. Now it is lost, or broken, we will never know.