Hard Clam (Meretrix meretrix) (Shell is fan-shaped, lacquer yellow-brown, the top of the shell has concentric fine radial ribs interwoven into a cloth-like pattern, inside the shell is gray-yellow.)
【Naming】
【Source】
Shen Nong’s Classic of Materia Medica, Upper Class
【Frequency of Use】
D (Relatively Uncommon)
【Botanical Origin】
Shells of the hard clam Meretrix meretrix L. or the Asiatic hard clam Cyclina sinensis Gmelin, family Veneridae.
【Characteristics】
The shell is fan-shaped, strong, thick, and swollen. The top of the shell is slightly protruding and slightly curved forward, located near the front of the dorsal margin. The lunule is wide and oval. The escutcheon is prismatic, the ligament is long and protruding. The front edge of the shell is oval, and the rear edge is truncated. The surface is grayish-yellow or grayish-white, some with banded patterns or brown spots. The shell surface has fine radial ribs interwoven with concentric growth lines from the top of the shell, forming a cloth-like pattern. The inner surface of the shell is grayish-yellow, slightly purple. The texture is hard, the cross-section is layered, and slightly calcareous.
The hard clam is fan-shaped or triangular, with brownish-gray or silvery-gray rings, smooth and glossy. The inner surface has teeth, milky white or slightly purple. The texture is hard and heavy, and the fractured surface shows layered patterns. The Asiatic hard clam is nearly circular, bluish-white or yellowish-white, with tightly arranged concentric layers and several blue rings. The inner surface is milky white or bluish-white. The texture is hard and slightly brittle, and the layered patterns on the fractured surface are not obvious.
【Processing】
1. Clam Shell 2. Calcined Clam Shell
【Identification】
Zheng Lei Ben Cao: “Those that have passed through twenty or thirty generations are good,” “The smaller ones are better if they have been around for a long time.” Zheng Lei Ben Cao: “Tang Ben’s note says: The ones that are moist, glossy and clean are good,” “These come in different sizes, and the ones that have been around for a long time are better.” Pu Ji Fang: “Ge Fen (Clam Shell Powder)… the greenish-blue powder is the best, if there is no greenish-blue, the white one is also acceptable.” Ben Cao Gang Mu: “Sea Clam: Those that have passed through twenty or thirty generations are good,” “Sea Clam, the smaller ones are better,” “The ones that are glossy, clean and smooth are good.”
Good quality is smooth, yellowish-white, with a purple mouth (purple edge), free of mud and dirt, and not withered.
【Category】
Invertebrate Animals