what is the title explanation of this book??

Well, in this case, the title tells us exactly what the story is about. The pearl is a valuable thing of beauty; it can be the source of great wealth and fulfillment of dreams, and yet, it is anything but. The story of the pearl also alludes to the Biblical story in the Book of Matthew about "the pearl of great price."

In essence, the title describes a beautiful discovery and a not so beautiful tragedy.