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Shidan (Chalcanthite)

Taste: Sour, acrid; Nature: Cold; Toxicity: Toxic. Indications: Improves vision, treats eye pain, metallic wounds (injuries caused by metal weapons), various types of epilepsy and spasms, erosion and pain in the female genitalia, lithiasis with cold and fever sensations, metrorrhagia and metrostaxis (heavy or prolonged uterine bleeding unrelated to menstruation), various pathogenic qi and toxic vapors, promotes fertility, dissipates accumulations and masses (abdominal lumps), cough with rebellious Qi, and rat-sores (scrofula) and malignant ulcers. After refining and taking it orally, it prevents aging; long-term use increases longevity and may lead to immortality. It can transform iron into copper, and produce gold and silver. Alternative names: Bishi (Bishi Stone), Heishi (Black Stone), Qishi (Chess Stone), Tongle (Copper Le). Habitat: Valleys in Qiandao, Qing Mountain in Qiangliju. Harvest time: Gengzi day and Xinchou day in the second lunar month. (Shuiying [Hydrocotyle sibthorpioides] serves as its guiding herb; it is incompatible with Mugui [Cinnamomi Ramulus], Jungui [Cinnamomi Cortex], Yuanhua [Genkwa Flos], Xinyi [Magnoliae Flos], and Baiwei [Clerodendri Rhizoma].)

Tao Hongjing stated: The "Immortal Classics" mention the use of this substance here, but it is rarely used in folk prescriptions, and this drug is almost extinct. People occasionally collect it nowadays; its color is greenish-blue, resembling liuli (colored glaze) but with white veins, and it breaks easily. It is no longer found in Liangzhou and Xindu. Folk medicine uses green alum instead, which bears no resemblance to the genuine article. In the "Immortal Classics," it is also called Lizhishi (Lizhi Stone). The Commentary of the Tang Materia Medica states: This substance is found near copper deposits, resembling Cengqing (Azurite), mixed with green hues, with a very sour and bitter taste, and turns iron copper-colored when rubbed against it; this is the genuine product. Tao's description of a color resembling liuli refers to Jiangfan (Red Alum). Recently, some have used Jiangfan to substitute Shidan, or made fake products by kneading Qingfan (Green Alum) with vinegar; both are counterfeit. Genuine Shidan comes from Dongting Valley caves and Xueji Cave in Yuxiang County, Puzhou; pieces the size of a chicken egg are considered genuine. Minister Yuxi and others, according to Wu Shi: Shidan - Shen Nong: Sour, slightly cold; Ji Shi: Cold; Tong Jun: Acrid, toxic; Bian Que: Bitter, non-toxic. *Materia Medica on Properties* states: Shidan is a Sovereign herb, highly toxic. It breaks down heat toxins; Luying [Euphorbia humifusa] serves as its assistant herb. Ri Huazi stated: Sour, astringent, non-toxic. Treats dental caries and nasal polyps. Transparent and clear, those from Puzhou are superior.

The *Illustrated Classic* states: Shidan grows in valleys of Qiandao and Qing Mountain of Qiangliju; currently, only found in Yanshan County, Xinzhou. It grows in copper pits, obtained through collection and refining, though naturally occurring ones are especially precious and deep green in color. It acts most rapidly in emetics for wind-phlegm. Harvested on Gengzi and Xinchou days in the second lunar month. Su Gong stated: Genuine Shidan comes from Dongting Valley caves and Xueji Cave in Yuxiang County, Puzhou; pieces the size of a chicken egg are genuine. Physicians in the south often use it. He further elaborated: The best Shidan comes from Puzhou, large pieces like fists, small ones like peaches or chestnuts. When struck, cracks form layered patterns纵横ly; the color is green, turning greener upon long exposure to air, and the interior is also green. The next best grade comes from copper pits in Qujiang, Shangrao; grains are fine with sharp edges, resembling hairpins or rice grains. The Materia Medica commentary notes that counterfeits were made by kneading Qingfan with vinegar. This is no longer the case; now, coarse inferior Shidan is mixed with Nixiao (Saltpeter) and melted together. Current counterfeits are large, pale, opaque without grain structure, shatter easily without edges when struck. Some contain embedded stones, formed by shaving off the Shidan bed and adding slurry during casting, causing them to adhere upon solidification.

*Tang Ben Cao* supplements: Treats bloody dysentery (red and white discharge), sallow complexion, and cold uterus in women. *Waitai Miyao*: Treats toothache and tooth loss. Finely powder Shidan, mix with human breast milk, and apply to the painful tooth or socket three to four times daily. Relieves pain, promotes regrowth of teeth, restoring them to their original state after 100 days. Rinse thoroughly with fresh water daily. *Mei Shi Fang*: Treats Onychia (paronychia). Burn 1 liang of Shidan until smoke ceases, grind into powder, and apply to the wound. Healing occurs within four or five applications. *Shengjin Fang*: Treats all toxins. Powder Danzi Fan (Alum), form pills the size of a cockspur ginger using glutinous rice paste, coat with Zhusha (Cinnabar), and store with Cinnabar. Dissolve one pill in cold water for immediate cure. Another prescription: For mouth ulcers unresponsive to other treatments, take 0.5 liang of Danfan (Alum), place in a crucible, heat until red hot, remove fire toxicity by placing on ground overnight, grind finely. Apply a small amount to the ulcer daily, inducing vomiting of acid fluid and clear saliva; severe cases heal with one dose. *Tan Shi Xiao'er Fang*: Treats stroke-induced flaccid paralysis. Grind Danfan into flour-like powder within one day. Administer approximately 1 zi (approx. 1-2g) with warm vinegar water, inducing immediate expectoration of phlegm, leading to gradual improvement. *Taiqing Fuliian Lingsha Fa*: Shidan originates from Songshan and Puzhou, imbued with spiritual stone energy, resembling sese (gemstones). Shen Cunzhong's *Pen Tan*: Yanshan County, Xinzhou has bitter springs flowing into streams. Boiling the water yields Danfan (Alum); cooking Danfan produces copper; boiling Danfan in an iron pot over time transforms the pot into copper.