Colombian Emeralds are a value store nobody can track, and no divorce can rip off, no politician can declare emeralds illegal ( happend with gold ) , no De Beers can manipulate their value by manipulating the global supply.
A emerald will not trigger any warning on the airport ( gold and silver bars do )
The amount of gold and silver you can take with you in an airplane is limited and you need to "declare the value to the authorities"
Emeralds need neither be "declared" nor "valuated" at the airport - no "intrinsic duty or need to declare" exists.
So if you insist in your "privacy rights" emeralds are a "great vehicle to enforce them" against undue nosing in on your wealth from all kind of "actors"...