Learn to choose, in the right order.

Risks → shell quality → surface quality → natural character → size, pairing, price and popularity.

The first four layers establish the basis for a choice. Size, pairing, price and popularity come later. If an earlier layer is unresolved, a strong sales pitch cannot fill the gap.

Guzhi, often literally called “bone quality” in Chinese collector language, describes the overall solidity and foundation of the shell. We use “shell quality” here to make the meaning clearer in English.

Consider density in the hand, firmness, structure, sound, surface behaviour and long-term feedback together. It is an experience-based collector term, rather than a single laboratory measurement, and it is not equivalent to the number on a scale.

Pizhi refers to the condition, fineness and behaviour of the shell surface. Look for natural texture, stability, an even colour transition and a warm rather than harsh shine.

Youxing, or “oiliness”, describes a lasting warm, smooth feel in collector usage. It does not mean that a walnut is leaking oil, and it is not a reason to apply oil.

Ask for clear views in natural light, including the tip, base, sides and ridges. Compare shape and surface details without relying on flattering lighting.

A photo can show clues but cannot replace inspection of density, handling feel and the underlying condition. When evidence is insufficient, postpone the decision.