"When emeralds were first discovered in America, a Spaniard carried one to a lapidary in Italy, and asked him what it was worth; he was told a hundred escudos; he produced a second, which was larger, and that was valued at three hundred.
Overjoyed at this, he took the lapidary to his lodging, and showed him a chest full; but the Italian seeing so many, damped his joy by saying, "Aha! Ha! Senor, so many! These are worth one escudo.""
So as more were shown to him, the estimated price went from $100 up to $300, then with the chest back down to $1.