In the story of Yosef Mokir Shabbat, Yosef is a Jew who honors Shabbat above all, and ends up becoming very rich because of it.
There was a very rich Gentile who was told that all of his wealth would become Yosef's. He sold all his possessions and bought an extremely valuable pearl, which he kept in his hat. One day, the hat blew off while he was crossing a bridge, and a fish ate it. The fish was caught, Yosef bought it, and when he cut it open, he found the pearl inside. (Classic story, told in Masechet Shabbat 119a.)
But my question is, why did the Gentile buy a pearl? Surely he should have seen that a small thing like that is much more likely to get lost than his house full of wealth.