Yu Yu Liang (Limonite) (Rhomboid, reddish-brown, uneven and heavy, layered texture, powder easily adheres to other objects)
[Naming]
[Source]
Shen Nong’s Classic of Materia Medica, Superior Class
[Common Usage Level]
E
[Botanical Source]
Limonite ore containing iron oxide.
[Characteristics]
It is an irregular rhomboid or oval shape, generally 6-10cm long and 1-3cm thick. The surface is light brown or reddish-brown, mostly uneven, or covered with yellow powder. The oval-shaped ones rattle when shaken. The cross-section shows alternating layers of dark brown and light brown. The dark brown part is hard but can be crushed. The crushed surface is irregular and smooth, with layered or network-like patterns and yellow powder. The light brown part is relatively loose and can be scratched with a fingernail; the yellow powder easily adheres to other objects. It has an earthy smell, a bland taste, and no gritty feeling when chewed. Vinegar-processed Yu Yu Liang: similar in shape to the raw product, but more loose and brittle.
[Processing]
1. Grind into coarse powder 2. Calcined Yu Yu Liang
[Identification]
“The best is the one without sand,” according to *Annotations to the Classic of Herbal Medicine*. *Newly Revised Materia Medica* says, “Now it mostly comes from Dongyang, shaped like goose or duck eggs, with overlapping shells on the outside and fine yellow powder like cattail pollen inside. The best is the one without sand.” *Essentials of Materia Medica* says, “Yellow powder in stone, growing in ponds and marshes, is good without sand.” *Seeking Truth in Materia Medica* says, “Yellow water is the best.”
The best is the one that is intact, not broken, ocherous brown, and has layered textures without impurities in the cross-section. It is partially soluble in hydrochloric acid. Its solution exhibits various specific reactions of iron compounds.
[Category]
Minerals