Nacre

Primarily produced in the Chinese provinces of Anhui, Jiangsu, Hebei, Zhejiang.

Hyriopsis cumingii (Lea): Slightly uneven quadrangle shape. Shell surface has circles that are arranged in concentric rings. Back edges are raised up, forming a large triangular silk-like posterior wing that gets larger as it goes upward. Coat of the inner surface has obvious scars; anterior adductor muscle scar is oval shape, posterior adductor muscle scar is slightly triangular shape. Left and right shells all have 2 main teeth, the left shell has 2 long strip-like side teeth, right shell has one long strip-like side tooth; lustrous. Hard texture. slightly fishy odor, tasteless. Cristaria plicata (Leach): Uneven triangular shape. Back edges have crest that stretches to a large size as it goes upward. Coat of the inner surface and shell is slightly obvious; anterior adductor muscle scar is large wedge-like, posterior adductor muscle scar is irregular oval shape, corresponding longitudinal ribs and indented grooves of the inner surface and shell are present. Left and right shell all have one short and slightly thick back side tooth and one thin weak front side tooth, no main teeth. Pteria martensii (Dunker): Angled square shape, back ear is large, front ear is small, back edges are parallel, has very dense long growth line, flake-like shape. Adductor muscle scar is large, long, with one raised long main tooth. Smooth, brittle texture, powder or small flakes when broken, translucent. faint odor, tasteless.

Superior medicinal material is large, white, with ‘pearl sheen’.

Salty, cold.

Calms liver, subdues yang, settles fright, brightens eyes. Apply to headache and dizziness, vexation and insomnia, liver heat and red eye, liver deficiency and blur vision.

‘Pearl sheen’: this refers to the smooth surface of pearls (zhen zhu) and mother-of-pearl (zhen zhu mu), which present with a translucent luster of light pink or other distinctive colors.