Introduction to Gan Tu
Gan Tu, a Chinese herbal medicine, is a type of bentonite clay. Bentonite clay is a type of clay mainly composed of montmorillonite. It is mainly produced in Heilongjiang, Jilin, Liaoning, Hebei, Zhejiang, and other provinces. However, the mineral composition, impurity content, and adsorption properties may vary in different locations or even within the same location. It has detoxifying effects and is used for food or mushroom poisoning.
Chinese Name: Gan Tu
Crystal System: Monoclinic crystal system
Color: White or gray or light pink
Luster: Earthy luster
Streak: White
Hardness: Low, can be scratched with a fingernail
Distribution: Heilongjiang, Jilin, Liaoning, Hebei, Zhejiang
Toxicity: Non-toxic
English Name: Montmorillonite
Other Names: Bai Dan, Bai Dian, Dan Dao, Tu Jing
Source: Listed in the book "Ben Cao Shi Yi".
Source of Medicinal Materials: Bentonite clay
Latin Name: Montmorillonite
Original Form: Bentonite clay mainly composed of montmorillonite
Montmorillonite Crystal Structure: Monoclinic crystal system. It is usually amorphous in the form of earthy aggregates, sometimes in the form of small scales or granules. It is white, or light gray, light red, light green, etc. The streak is white. It has an earthy luster. The complete cleavage of a single crystal cannot be seen with the naked eye. It has a hardness of 1-2. The aggregates are soft and have a slippery feel. The relative density is 2-2.7. It expands when in contact with water, increasing its volume several times and becoming a paste-like substance. It has strong adsorption and ion exchange capabilities.
Habitat: Formed by the alteration of tuff or other volcanic rocks under alkaline water.
Distribution: Mainly produced in Heilongjiang, Jilin, Liaoning, Hebei, Zhejiang, and other provinces.
Appearance and Identification: Gan Tu is in the form of clumps, white or gray, and some may be light pink due to impurities. It is opaque with an earthy luster. It has low hardness and can be scratched with a fingernail. It has strong water absorption and feels suction when licked. It swells and disintegrates into fine particles or powder when placed in water. It has a smooth and greasy feel. It has a slight earthy odor and a mild taste. The preferred characteristics are white color, smooth and greasy feel, and strong water absorption.
Microscopic Identification: Under transmitted polarized light microscope, the thin section is colorless with a slight green tint. Microcrystalline and cryptocrystalline montmorillonite often have uniformly distributed particles of other clay minerals, such as quartz, rock flour, etc., with particle sizes generally below 0.001mm. Microcrystalline montmorillonite often appears as vein-like or reticulated distribution in rocks, with localized patches and scales; the particle size of scales is about 0.002mm.
Effects and Functions of Gan Tu
Effects of Gan Tu: Non-toxic.
Functions of Gan Tu:
Used to treat mushroom poisoning. It is taken orally mixed with hot soup.
Images of Gan Tu:
