The Unique Abacus of Nadia Sunkin is a 723 years old piece made by Nadia Sunkin, a merchant living in Jerusalem.
Considering its age and the quality of the work, people consider it of considerable value.
It is engraved with central asian patterns and some symbols pertaining to Gnosticism.
This piece doesn't exist, but as a legend. It is said that in the year 1291, Nadia Sunkin, the owner, made use of it in Jerusalem to empower the Sunkin family. Now it is lost, or broken, we will never know.