Technical Specifications
Collection Methods: Collection requires preserving the stone's original appearance; no artificial carving or alteration is permitted, and the stone must remain free of any damage. For small specimens, manual collection suffices; for medium-sized components and pieces, appropriate tools-such as iron chisels for prying or steel saws for cutting-may be employed; for large specimens, modern mechanized tools may be utilized.
Cleaning: *Yin* (Yin-type) Ying stones are first immersed in an industrial nitric acid solution with a pH of 2.0 to reveal their true underlying color; *Yang* (Yang-type) Ying stones are cleaned using clear water to preserve the natural color and patina of the stone's surface.
Quality Characteristics
Color: Colors include black, grayish-black, bluish-gray, light green, red, white, yellow, and others. Pure black specimens are considered superior; red and multicolored specimens are rare. Specimens featuring evenly distributed mineral veins and a lustrous, clear coloration are classified as top-grade.
Key Attributes: *Shou* (Leanness), *Zhou* (Wrinkling), *Lou* (Leakage/Perforation), and *Tou* (Transparency/Interconnectedness). *Shou* refers to a gaunt, rugged physique; *Zhou* refers to deep surface textures and prominent, sharp angles; *Lou* refers to the moderate and orderly distribution of drip-like channels and perforations; *Tou* refers to the interconnectedness of the stone's internal cavities and pores. *Yin* stones typically feature a smooth, glossy surface with numerous pores, emphasizing the attributes of *Lou* and *Tou*. *Yang* stones typically feature a surface with sharp angles and deep folds but fewer pores, emphasizing the attributes of *Shou* and *Zhou*.
Ying Stone Grading: Classified into "Treasures," "Fine Specimens," and "Standard Specimens." Specimens that possess all four key attributes-*Shou*, *Zhou*, *Lou*, and *Tou*-and are aesthetically pleasing from all four sides are classified as "Treasures." Specimens that possess all four key attributes and feature a pure black, pure white, pure yellow, or multicolored coloration are classified as "Fine Specimens." Specimens that possess at least one of the four key attributes-*Shou*, *Zhou*, *Lou*, or *Tou*-are classified as "Standard Specimens."
