Concha Margaritifera
Nacre

Source:
The shell of Hyriopsis cumingii (Lea)(Fam. Unionidae).

Distribution:
Mainly in Chinese provinces such as Hebei, Anhui, Jiangsu and Zhejiang.

Harvest & Processing:
Harvest clams anytime during the year; remove flesh and mud; wash shells clean; boil hard in alkaline water; rinse in fresh water; take out and scrape off outer black skin; dry shells under the sun or by heat.

Description:
When whole, shells roughly scalene (with ridges of unequal length) quadrangle in shape. Outer surface marked with concentric growth rings. Posterior dorsal brim raised, forming a big triangular sail-like proximal limb. Inner surface with a conspicuous pallial scar; anterior adductor scar egg-shaped in outline, posterior adductor scar slightly triangular. Left and right valves each with 2 pseudocardinal teeth; left valve with 2 long and thin lateral teeth, right valve with 1 long and thin lateral tooth. Lustrous. Hard. Odour: slightly fishy; taste: mild.

Indications:
1. Dizziness, headache, tinnitus
2. Red eyes, night blindness, blurring of vision, nebula, cataract
3. Irritability, insomnia, palpitation, forgetfulness
4. Peptic ulcer
5. Hypertension

Chemical Composition:
Mainly contains calcium carbonate (CaCO3), a variety of inorganic elements and amino acids.

Note:
According to C.P., also used for medicinal purposes is the shell of animals such as Pinctada martensii (Dunker) (Fam. Pteriidae) and Cristaria plicata (Leach), the latter species belonging to the same family as H. cumingii (Lea).