My oldest dated British coin, from 1553 Scotland, and whence Queen Mary was only 11 years old: The earliest dated British coins were from the reign of James V and were dated 1539, gold of course!
A ducat struck in Frankfurt am Main in 1796 while the city was occupied by french troops. An interesting and historical coin from the napoleonic era.
I say let the tiny flakes get melted into coins Beautiful gold specimens are stunning and I'm sure most of the early finds were crushed and melted for subsistence living and that relatively few natural nuggets and fewer crystal specimens exist today.