A stone was found on the fish's bone, probably because the fish swallowed the stone by mistake when feeding. In this case, stone is usually of little value because it is not a rare gem or mineral.

However, if this stone has a special shape, color or texture, or contains some valuable minerals, then it may have certain ornamental or collection value. For example, some stones may be used as decorations or carving materials, while some special minerals may attract collectors.

To judge whether this stone is valuable, you can consider the following points:

1. Observe the shape, color and texture of the stone. If it has a unique shape, bright color or special texture, then it may have certain ornamental value.

2. Understand the source and background of the stone. If this stone comes from a famous gem producing area or has an interesting legend, then it may have a higher collection value.

3. consult a professional. If you are not sure about the value of this stone, you can consult a professional, such as a jeweler, collector or geologist.

In a word, the stone found on fish is not necessarily priceless, but if it has a special shape, color or texture, or contains valuable minerals, it may have certain ornamental or collection value. To determine the value of this stone, you can observe its appearance, understand its source and background, or consult a professional.