一名寒水石，一名盐精石。
畏地榆。制丹砂。解巴豆毒。
辛、咸、寒。入足少阴经血分。凉血降火。治时气热盛，五脏伏热，皮如火烧，伤寒劳
复，坚齿明目，涂小儿丹毒。
得朱砂、甘草、冰片研细末，掺牙龈出血。得滑石、葵子，治男女转脬。（过忍小便而致者。）
卤地积盐之下渗入土中，年久至泉，结而成石，清莹有齿，棱如马牙硝，入水即化。以生姜
自然汁煮干，研用。胃弱者禁用。
古方所用寒水石，是此石。唐宋诸方寒水石，是石膏。近方寒水石，是长石、方解石。
即玄精石
制硫黄、丹砂。
咸，寒。治暑火热泻，疗伤寒壮热。汤火伤，调油敷。已破者，干掺。得牛黄、朱砂、
冰片，掺重舌涎出。（先以针
挑去血，盐汤漱口。）得生甘草，治目中赤脉。配半夏、硫黄，治寒热霍乱。配硫黄、硝石，
治上盛下虚，救阴助阳，有
扶危拯逆之功。
咸卤津液，流渗入土，年久结成石，片片状如龟背，六角，青白莹彻者良。今世所用玄
精，乃绛州山中所出绛石，
非玄精也。
一名皮硝，一名盐硝。
石苇为之使。畏京三棱。恶麦句姜。
辛、苦、咸、微寒。有小毒。逐六腑积聚，散三焦火郁。治天行热疾，除停痰痞满，疗
伤寒发狂，利大小便，落死
胎。得独蒜、大黄捣饼，贴痞块。配僵蚕、硼砂、脑子，吹风热喉痹。配硫黄、白矾、滑石，
治伏暑泻痢。配矾石、大
麦粥，治女劳黑疸。（发热恶寒，膀胱急，小腹满，身黄额黑，腹胀如水，大便溏黑，小便
黄。）
瓷瓶 赤，投硝石于内，每四两，用鸡肠草、柏子仁共廿五个，丸如珠子大，以丸 尽
为度。虚极似实等症，勿得
误投。孕妇禁用。朴硝黄者伤人，赤者杀人。
Ningshui Shi (Calcitum), also known as Hanshui Shi (Cold Water Stone) and Yanjing Shi (Salt Essence Stone).
It is incompatible with Diyu (Sanguisorbae Radix). It is processed with Zhusha (Cinnabaris). It resolves the toxicity of Badou (Crotonis Fructus).
Pungent, salty, cold. Enters the blood aspect of the Foot-Shaoyin Kidney Meridian. Cools blood and descends fire. Treats epidemic febrile diseases with excessive heat, latent heat in the five zang organs, skin feeling like burning fire, relapse of Shanghan (Cold Damage) due to overexertion, strengthens teeth and brightens eyes, and topical application treats Xia'er Dandu (pediatric erysipelas-like dermatitis).
Combined with Zhusha (Cinnabaris), Gancao (Glycyrrhizae Radix et Rhizoma), and Bingpian (Borneolum Syntheticum), ground into fine powder, and sprinkled on gums to treat gingival bleeding. Combined with Huashi (Talcum) and Kuizi (Abutilonis Semen), it treats Zhuanpao (retention of urine) in both men and women. (Caused by enduring the urge to urinate for too long.)
This stone forms when salt accumulated in saline soil seeps into the earth, reaches underground springs over many years, and crystallizes into stone. It is clear, lustrous, and toothed, resembling Mayaxiao (Mirabilite crystals), and dissolves immediately upon contact with water. It is boiled dry with fresh ginger juice and then ground for use. Contraindicated in patients with weak stomach qi.
The Hanshui Shi used in ancient prescriptions refers to this stone. The Hanshui Shi recorded in Song and Tang dynasty prescriptions refers to Shigao (Gypsum Fibrosum). The Hanshui Shi in recent prescriptions refers to Changshi (Albite) or Fangjieshi (Calcite).
Taiyi Xuanjing Shi, which is Xuanjing Shi.
Processed with Liuhuang (Sulfur) and Zhusha (Cinnabaris).
Salty, cold. Treats summerheat-fire diarrhea; cures high fever caused by Shanghan (Cold Damage). For scalds and burns, mix with oil and apply topically. If the skin is already broken, sprinkle the dry powder directly. Combined with Niuhuang (Calculus Bovis), Zhusha (Cinnabaris), and Bingpian (Borneolum Syntheticum), sprinkled to treat Chongshe (double tongue/swelling of sublingual veins), causing saliva to drain. (First puncture with a needle to release blood, then rinse mouth with salt water.) Combined with Sheng Gancao (Raw Glycyrrhizae Radix et Rhizoma), it treats red vessels in the eyes. Paired with Banxia (Pinelliae Rhizoma) and Liuhuang (Sulfur), it treats cholera with alternating chills and fever. Paired with Liuhuang (Sulfur) and Xiaoshi (Natrii Sulfas), it treats conditions of excess above and deficiency below, rescuing yin and assisting yang, possessing the merit of supporting critical cases and reversing adverse conditions.
This stone forms when saline brine flows and seeps into the earth, crystallizing over many years into stones that are layered like turtle shells, hexagonal in shape. Those that are cyan-white and transparent are of good quality. The Xuanjing used in the current era is actually Jiangshi (Jiang Stone) from mountains in Jiangzhou, not true Xuanjing.
Pu Xiao, also known as Pixiao and Yanxiao.
Shiwei (Pyroses Folium) acts as its guiding herb (shi). It is incompatible with Jing Sanleng (Sparganii Rhizoma). It is aversive to Maijujiang (Zingiberis Rhizoma Recens).
Pungent, bitter, salty, slightly cold. Slightly toxic. Drains accumulations in the six fu organs; disperses fire stagnation in the Sanjiao. Treats epidemic febrile diseases; eliminates retained phlegm and epigastric fullness; cures mania caused by Shanghan (Cold Damage); promotes urination and defecation; expels dead fetus. Combined with Dusuan (Allii Sativi Bulbus) and Dahuang (Rhei Radix et Rhizoma), pounded into cakes, and applied to epigastric masses. Paired with Jiangcan (Bombyx Batryticatus), Pengsha (Borax), and Naozi (Borneolum), it treats wind-heat Houbi (sore throat with obstruction). Paired with Liuhuang (Sulfur), Baifan (Alumen), and Huashi (Talcum), it treats dysentery caused by hidden summerheat. Paired with Fanshi (Alumen) and Damai Zhou (Hordeum Vulgare Porridge), it treats Nulao Heidan (black jaundice due to sexual exhaustion). (Symptoms include fever and aversion to cold, urgency of the bladder, fullness of the lower abdomen, yellow body with black forehead, abdominal distension like water retention, loose black stools, and yellow urine.)
Heat a porcelain bottle until red, throw Pu Xiao (Mirabilite) inside. For every four liang of Pu Xiao, use twenty-five Ji Changcao (Phyllanthi urinariae Herba) and Baizi Ren (Biota Seed), pill them into bead-sized pills, using up the pills as the limit. Do not mistakenly administer to patients with extreme deficiency mimicking excess. Contraindicated in pregnant women. Yellow Pu Xiao harms people; red Pu Xiao kills people.