stylistic:style_transfer, quality:correction, structural:summarization, linguistic:paraphrasing
In culture

Large, symmetrically shaped, and sometimes intricately carved walnut shells (mainly from J. hopeiensis) are valued collectibles in China where they are rotated in hand as a plaything or as decoration. They are also an investment and status symbol, with some carvings having high monetary value if unique. Pairs of walnuts are sometimes sold in their green husks for a form of gambling known as du qing pi.