如长石，但理石如石膏顺理而细，其非顺理而细者为长石，治疗亦不相辽。
铁于矿中炼出者，谓之生铁。铁落，断而落者也。 （音柔）铁，铁炒成熟铁也。刚铁
，炼铁，去滓者也。铁精、针沙、铁浆，以上三等，取汁，各依经用。铁华粉、铁粉，以上
二等，烧 取。马衔、秤锤、车辖、杵锯，以上五等，特以其意使之耳。其生铁既自火中炼
石
而出，世谓之生铁。亦如炒脂麻取油，谓之生油，其义亦同，白油麻条中已着。铁粉，以生
姜汁调擦眉上，生眉毛。钢铁，今用柔铁屈盘，乃以生铁陷其间，泥封炼之， 令相入，
谓之围钢，又曰灌钢。此盖草创之钢，亦不免伪也。盖生铁之坚，及三四炼，则生铁亦自熟
，却是柔铁，而天下莫以为非。磁州炼坊，方识真钢。凡铁之有钢，如面之有筋，灌 揉
面既尽，筋乃见，炼钢亦然。恒取精铁一百余斤，每锻一火，称之遂轻。累锻称之，至于不
减
耗，此则纯钢也。实铁之精纯者，虽百炼不耗矣。其色清明，磨莹之，则黯黯而清且黑。亦
有炼之尽，全无钢者，系地之所产精粗尔。前所谓铁精者，其说有二∶陶隐居言出 灶中，
如尘、紫色、轻者为佳，亦以摩莹铜器用之。日华子又云∶犁 尖浸水中名为铁精。本条既
言化铜，则隐居所说是。盖锻灶中尘紫摩铜则明，浸犁 尖水非是。
As for Changshi (Long Stone), only Lishi (Reticulated Stone) is fine and follows the grain; those that are fine but do not follow the grain are called Changshi, yet their therapeutic effects are not significantly different.
Iron smelted from ore is called Shengtie (Pig Iron). Tielluo (Iron Scale/Filings) refers to iron fragments broken off during forging. (Pronounced 'rou') Tie (Iron) refers to iron stir-fried until it becomes Shutie (Wrought Iron). Gangtie (Hard Iron) is refined iron with impurities removed. Tiejing (Iron Essence), Zhensha (Needle Sand), and Tiejiang (Iron Slurry): for these three, the juice/liquid is extracted and used according to specific meridian indications. Tiehuafen (Iron Flower Powder) and Tiefen (Iron Powder): for these two, they are obtained through calcination. Maxian (Horse Bit), Chengchui (Scale Weight), Chexia (Axle Cap), Chuju (Mortar Pestle and Saw): for these five, they are used merely based on their symbolic meaning or shape. Since Shengtie (Pig Iron) is smelted directly from stone in fire, the world calls it Shengtie. This is similar to pressing sesame seeds to obtain oil, called Shengyou (Raw Oil); the principle is the same, as mentioned in the section on Baiyouma (White Sesame). Tiefen (Iron Powder), when mixed with fresh ginger juice and applied to the eyebrows, promotes eyebrow growth. Gangtie (Steel) is now made by coiling Rouruo (Soft Iron/Wrought Iron), placing Shengtie (Pig Iron) inside, sealing it with mud, and smelting it so that they merge. This is called Weigang (Encased Steel) or Guangguan (Poured Steel). This represents an early, rudimentary method of steelmaking, which inevitably contains elements of falsification. Generally, Shengtie (Pig Iron) is hard; after three or four refinements, the Shengtie itself becomes mature, turning into Rouruo (Soft Iron/Wrought Iron), a fact accepted universally. Only the smelters in Cizhou can identify true steel. The presence of steel in iron is like gluten in flour; only after kneading and working the dough thoroughly does the gluten appear. Smelting steel follows the same logic. Typically, over one hundred jin of refined iron is taken. After each hammering cycle, the weight decreases. Upon repeated hammering and weighing, when the weight no longer decreases, this is pure gang (steel). It is the most pure essence of iron; even after a hundred refinements, it does not diminish. Its color is clear and bright; after polishing, it appears deep, clear, and black. There are also cases where all iron is smelted away with no steel remaining, depending on the quality (fine or coarse) of the ore produced in that region. Regarding the previously mentioned Tiejing (Iron Essence), there are two theories: Tao Hongjing stated it comes from the furnace, resembling dust, purple in color, and light in texture, which is considered superior, and is also used to polish copper vessels. Ri Huazi claimed that water in which a plowshare tip has been soaked is called Tiejing (Iron Essence). Since the text mentions its ability to dissolve copper, Tao Hongjing’s description is correct. Generally, the purple dust from the forge polishes copper to brightness, whereas soaking a plowshare in water is incorrect.