In ancient times, a man of the State of Song picked up a stone in Linzi. He examined it over and over and regarded it as a treasure. He quickly took it home, wrapped it up in dozens of silk layers, then put it in a leather box. But he still felt uneasy, so he covered the box with dozens of boxes.

The man of Song thought the man who knew about treasures was envious of him and trying to cheat him. Much displeased, he said:

When the man who knew about treasures saw it, he nearly burst into laughter, but quickly covered his mouth with his hand. He whispered close to the other's ear:"This is a piece of stone, as worthless as a tile."

When a man who could identify treasures heard of this, he went at once to this man and asked to have a look at the treasure.

To be prudent, this man of Song took a bath, burned incense, cleansed his mind, calmed his mood, and went in for self -- cultivation for seven days. Then be put on ceremonial robes, respectfully took out the box, and carefully took the stone out of the box.

"Merchants always say others' wares are worthless, and doctors always say patients' illnesses are very serious, so that they themselves can make more money. I will not be fooled!"

Thereafter, he treasured this stone even more, and kept it in a very safe place.