Fish bone, also known as herring stone, is yellow in color, heart-shaped, hard and crystal clear as jade, and is regarded as a rare product in Hakka area. You can string a red rope around a child's wrist, which is said to have the functions of avoiding evil spirits, preventing children from being frightened and Nafunalu.

The concept of herring stone or herring stone powder often appears in the treasure-seeking chapters of fairy tales and the names of props in online games to ward off evil spirits and detoxify. Such as the novel "Ghost Blows the Lamp" and the online game "Love between Swordsman 3". There are many kinds of herring, and the herring (black pomfret) with this stone, also known as snail green, is a kind of freshwater fish, weighing dozens of kilograms.

This kind of fish likes to eat snails, and herring stone is suspected to have evolved from the hyperplastic hard bone used to crush snails in the throat and jaw for many years. And it often takes dozens of kilograms of big fish. Other ordinary fish don't have this kind of stone, so it is rare and precious. After core removal, the material of fish stone is stable and can be preserved for a long time.

Reference: Herring Stone-Baidu Encyclopedia