Calamine powder, also known as Lu Gan Shi, is a common Chinese herb mainly used for skin conditions. Thanks to its tremendous therapeutic effect for sunburn, prickly heat, eczema, rashes, hives, etc., it becomes an important ingredient in many antipruritics, among which calamine lotion is the best known one. As a matter of fact, calamine is more than just an anti-itching agent and it has long been used for a variety of diseases in traditional Chinese medicine (TCM).
What is calamine powder?
Actually it refers to the powder form of smithsonite, which is one kind of carbonate minerals and contains mainly carbon zinc (ZnCO3). So, other names of this herb include Smithsonite, Calamina, Smithsonitum, hydrozincite, and so on. In China it is basically produced in Guangxi, Hunan, Sichuan, Yunnan and other places. It can be dug all through the year. After that, medicinally it needs to remove the soil and miscellaneous stones, wash, dry in the sun, and calcine. Besides, after the calcination it needs to be quenched with vinegar or San Huang Tang (The combination of Coptis, Phellodendron and rhubarb). And it is usually used levigated.
The crystal structure of smithsonite belongs to the trigonal system. Single crystal is rhombohedral or ditrigonal-scalenohedral, which however is extremely rare. And normally it is the aggregates of shapes of stalactite, lump, earth, and hull. The pure one is white but often dyed gray, yellow, light green or light brown. It is from transparent to translucent, and with gloss of glass or dull earthy luster. And sometimes there is soft luster of pearls on the crystal surface. Hardness is from 4.5 to 5. It is brittle and irregular-shaped fracture surface. Relative density is from 4 to 4.5.
Main chemical compositions of smithsonite are zinc carbonate (ZnCO3). In addition, it still contains 0.27% calcium oxide (CaO), 0.45% magnesium oxide (MgO), 0.58% iron oxide (Fe2O3), and 0.01% manganese oxide (MnO). Among them zinc is often replaced by iron (bivalent). And some still contains a small amount of cobalt, copper, cadmium, lead, and trace amounts of germanium and indium.
Calamine powder benefits
Since calamine lotion is one of the most widely used calamine powder products, it makes sense to use it to illustrate how calamine works. So, what is calamine lotion? Actually this is a type of lotion made of powder with calamine, which is used clinically as a topical dermatological formulation. The so-called lotion refers to the suspension made of water-insoluble powder, water, and a small amount of glycerol. Main ingredients of calamina lotion are calamine and zinc oxide, which can astringe and protect skin. It is good for skin problems, such as acne, chicken pox, diaper rash, eczema, impetigo, dermatitis rhus, drug-induced dermatitis, anal pruritus, blepharitis, dacryocystitis, and so on. In addition to the calamine lotion, you can also choose from other calamine products, such as calamine powder face masks, cream, spray, soap, and more.
Modern pharmacology of calamine lotion powder
The zinc carbonate contained is insoluble in water. In external use it can partially absorb topical wound exudates, prevent corrosion, astringe the wound, reduce inflammation, stops the itching, protect the wound, and inhibit the growth of Staphylococcus locally.
Selected herbal remedies on calamine clay powder
Based on the Chinese Materia Medica indicates, it is sweet in flavor and neutral or warm, and non-toxic in properties. It goes to meridians of liver, spleen, and lung. Primary functions are removing corneal opacities to improve eyesight, astringing dampness to relieve itching, and healing wounds to promote tissue regeneration. Major calamine powder uses and indications include sore red swollen eyes, red painful swelling of the eyelid, excessive tearing, photophobia, nebula, pterygium, non-healing ulcer, eczema, and itching of the pudendum and vagina. It is usually applied externally only.
1. Shen Ying San from Yu Yuan Yao Fang (Prescriptions from Royal Drug Museum). It is combined with Xuan Ming Fen (Natrium sulfuricum) to treat red swollen eyes.
2. Zhi Lei San from Zheng Zhi Zhun Sheng (The Level-line of Patterns and Treatment). It works with Hai Piao Xiao (Cuttlefish Bone) and Bing Pian (Borneol) to treat epiphora induced by wind.
3. Ping Ji San from Prescriptions from Royal Drug Museum. It is used together with Long Gu (Dragon bones) to cure non-healing ulcer.
4. Huang Lian Lu Gan Shi San from The Level-line of Patterns and Treatment. It is formulated with Huang Lian (Coptis root) and Borneol to cure rotten rim of the eye and photophobia.
5. Hong Mian San from Yi Fang Da Cheng Lun (The Theory of Comprehensive Medical Prescription). It is designed with Ku Fan (dried alum), Rouge, and She Xiang (Moschus) to treat acute or chronic suppurative ear disease.
Calamine powder side effects and contraindications
Some calamine powder contains lead and cadmium, which have considerable toxicity. And the oral administration of it can generate zinc chloride inside the stomach and thus stimulate and corrode the gastrointestinal tract. So, normally it shouldn’t be taken orally.