（本经中品）
用磨铁峰，铁便指南，其既济象，为水火之征兆也。无情化有情，理固然矣。
【气味】辛寒，无毒。
【主治】主周痹风湿，肢节中痛，不可持物，洗洗酸消，除大热烦满，及耳聋。
【核】曰∶生太山山谷，及磁山山阴，有铁处则生其阳。今徐州，及南海傍山中亦有。
磁州者，岁贡最佳，能吸铁，虚连数十铁，或一二斤刀器，回转不落者，尤良。采无时。石
中有孔，孔中有黄赤色，其上有细毛，功用更胜。南川异物志云∶涨海崎头，水浅而多磁石，
徼
并中麻石。二石俱似磁石，只是吸铁不得。而中麻石心更有赤，皮且粗，是铁山石也。误食
令人生恶疮，不可疗。真磁石一片，四面吸铁一斤者，曰延年沙；只吸八两者，曰续采石；
五两者，曰磁石。磁磨针峰，则指南。其法取新纩中独缕，以半芥子许蜡，缀于针腰，无风
处垂之，针尝指南。以针横贯灯心，浮水上，亦尝指南。物理相感如此。土宿真君云∶铁受
太阳之气，始生之初，卤石产焉。百五十年而成磁石，又二百年孕而成铁。修治一斤，用五
花皮、地榆各一镒，取绵十五两，三件并锉。于石上，捶作二三十块。将石入瓷瓶中，下草
药，以东流水煮三日夜，取出，拭干，布裹再捶细，乃碾如尘，水飞过，再碾用。茈胡为之
使，杀铁毒，消金，恶牡丹、莽草，畏黄石脂。
【 】曰∶始生之初，卤石产焉，久之孕而成铁。磁母，铁子也。磁之 铁，互为嘘吸，
无情之情，气相感召，故周痹风湿，及湿流肢节，致肢节中痛，洗洗酸消也，不能持物，此
手不 物；不能听声，此耳不 声；并可治目不 色，鼻不 香，舌不 味，与痈肿鼠 ，
颈核喉痛之身不 触，皆以类推。总属假借，大热是因，烦满是证，磁属八石水而位于坎，
对待治之，寒热温凉则逆也。
【本经中品】
利用磁石摩擦铁针，铁针便能指向南方，这体现了水火既济的卦象，是水火相交的征兆。无生命之物转化为有感应之性，道理本来就是这样。
【主治】主要治疗周痹风湿，肢体关节疼痛，无法持握物品，身体感觉寒冷且酸痛，清除大热烦闷，以及耳聋。
【核】曰：磁石产于泰山山谷，以及磁山山的北面（阴面），在有铁矿的地方则产生其阳气。现在的徐州，以及南海旁边的山中也有出产。
磁州进贡的磁石最佳，能够吸附铁器，虚悬连接数十块铁片，或者一两斤重的刀具器具，旋转而不掉落，这种尤其好。采集没有固定时间。石头中有孔，孔中有黄赤色的物质，上面有细毛，功效更好。《南川异物志》说：涨海崎头，水浅而多磁石，还有中麻石。这两种石头都类似磁石，只是不能吸铁。而中麻石心部更红，表皮粗糙，这是铁山石。误食会让人生恶疮，无法治愈。真正的磁石一片能吸附一斤铁的，称为“延年沙”；只能吸附八两的，称为“续采石”；五两的，称为“磁石”。用磁石磨针锋，针就能指南。方法是取新丝绵中的单根丝线，用半粒芥子大小的蜡，将丝线缀在针腰上，在无风处悬挂，针常指南方。将针横穿灯芯草，浮在水面上，也常指南方。物理相互感应的道理如此。《土宿真君》说：铁在接受太阳之气后，最初生成时，卤石便产生了。经过一百五十年形成磁石，又过二百年孕育成铁。修治一斤磁石，需用五花皮、地榆各一镒（古代重量单位，约合十二两或二十四两，此处依原文保留），取绵十五两，三件一起锉碎。放在石头上，捶打成二三十块。将石头放入瓷瓶中，下面放草药，用东流水煮三个日夜，取出，擦干，用布包裹再捶细，然后碾成尘状，用水飞法处理，再碾细使用。柴胡作为引经药，能消除铁毒，化解金气，与牡丹、莽草相恶，畏惧黄石脂。
【按】曰：最初生成时，卤石便产生了，久而久之孕育成铁。磁是母，铁是子。磁与铁之间，互相呼吸引导，无生命之物却有情意，气息相互感召，所以周痹风湿，以及湿气流注肢体关节，导致关节疼痛，身体寒冷且酸痛，不能持物，这是因为手不能感知物体；不能听声音，这是因为耳不能感知声音；都可以类推治疗眼不能感知颜色，鼻不能感知气味，舌不能感知味道，以及痈肿、鼠瘰、颈核、喉痛等身体不能感知触碰的情况，都是以此类推。总体属于借喻，大热是病因，烦满是证候，磁石属八石之水，位于坎卦，以对待之法治疗，寒热温凉则是逆治。
[Shennong Bencao Jing, Middle Grade]
By rubbing an iron needle with magnetite (Cishi), the needle points south. This reflects the hexagram Ji Ji (After Completion / Water and Fire in their proper places), serving as a sign of the interaction between Water and Fire. The transformation from lifeless matter to responsive entity follows natural principles.
[Flavor and Toxicity] Acrid, Cold, Non-toxic.
[Indications] Primarily treats generalized Bi syndrome (Zhou Bi) caused by Wind-Dampness, pain in the limbs and joints, inability to hold objects, a sensation of coldness and soreness/aching throughout the body, severe heat with vexation and fullness, and deafness.
[Verification] It is stated: Magnetite grows in the valleys of Mount Tai and on the shady slopes of Mount Ci. Where iron deposits exist, its Yang energy is generated. It is also found in modern Xuzhou and mountains near the South Sea.
Magnetite from Cizhou offered as tribute is the best; it can attract iron, suspending dozens of iron pieces or even knives and utensils weighing one or two jin, rotating without falling. Such quality is superior. There is no fixed time for harvesting. Stones with pores containing yellow-red substances and fine hairs on top have even better efficacy. *Nanchuan Yiwu Zhi* states: At Qitou in the Rising Sea, where waters are shallow, there is much magnetite and Zhongma stone. Both stones resemble magnetite but cannot attract iron. Zhongma stone has a redder core and rough skin; it is Iron Mountain Stone. Ingestion causes malignant sores that are incurable. A piece of true magnetite capable of attracting one jin of iron is called "Yannian Sha" (Longevity Sand); one attracting eight liang is called "Xucail Shi"; one attracting five liang is called "Cishi" (Magnetite). Rubbing a needle tip with magnetite makes it point south. The method involves taking a single thread from new cotton wadding, attaching it to the middle of the needle with wax the size of half a mustard seed, and hanging it in a windless place; the needle will consistently point south. Alternatively, threading the needle horizontally through a rush pith and floating it on water also results in it pointing south. This demonstrates the principle of physical resonance. *Tusu Zhenjun* states: When iron first receives Qi from the Sun, Luoshi (Halite/Niter) is produced initially. After 150 years, it becomes magnetite, and after another 200 years, it matures into iron. To process one jin of magnetite, use Wuhua Pi (Bark of Five-Flowered Tree) and Diyu (Sanguisorbae Radix), each one yi (an ancient weight unit), along with fifteen liang of silk floss. Chop all three together. Pound them into 20-30 pieces on a stone. Place the stone in a porcelain bottle, add herbal medicines below, and boil in flowing water from the east for three days and nights. Remove, wipe dry, wrap in cloth, pound finely again, then grind into dust. Process using the water flotation method (Shuifei), then grind again for use. Bupleuri Radix (Chaihu) acts as an assistant drug, neutralizing iron toxicity and resolving metal-related issues. It is incompatible with Peony Root (Mudanpi) and Aconitum Lateralis Preparatum (Mangcao - note: context implies toxic herb incompatibility), and fears Huangshizhi (Yellow Earth Resin).
[Commentary] It is stated: Initially, Luoshi is produced, which over time matures into iron. Magnetite is the mother; iron is the child. Magnetite and iron inhale and exhale each other's Qi. Though lifeless, they possess a form of sentiment, and their energies resonate mutually. Thus, they treat generalized Bi syndrome due to Wind-Dampness, dampness flowing into limb joints causing pain, coldness, and soreness, inability to hold objects (indicating the hand's failure to perceive objects), and inability to hear sounds (indicating the ear's failure to perceive sounds). By analogy, this extends to treating eyes failing to perceive colors, noses failing to perceive odors, tongues failing to perceive tastes, and conditions like carbuncles, scrofula, cervical lymphadenopathy, and throat pain where the body fails to perceive touch. These are all analogical applications. Generally, severe heat is the cause, and vexation/fullness is the manifestation. Magnetite belongs to the Eight Minerals associated with Water and is located in the Kan trigram. It treats these conditions through counteracting methods; thus, Cold, Heat, Warmth, and Coolness act inversely.