Hi
I haven't purchased bitcoins so far, although I read some stuff about it. Let say that one has gold/silver but wish to exchange it for bitcoins in order to cross a border, is it possible to "test" the validity of a bicoin that an individual propose you?
I know that you can purchase gold online (from a company) with bitcoins but above the spot price, maybe there is such an operationnal network where individuals simply swap it? If so how would I proceed to test if a bitcoin is valid?