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Taiyi Yuyuliang (Taiyi Hematite), its detailed description has already been provided under the entry for Yuyuliang (Hematitum).

Wumingyi (Pyrolusite), originates from Dasiguo (ancient Arab region), grows on rocks. It is now also found in the rocky mountains of Guangzhou and in Longji Mountain, eight li south of Yizhou. It is dark brown; large pieces are like bullet shots, small ones like ink stones. It can be harvested at any time. *Shennong Bencao Jing* (Divine Farmer's Materia Medica) states: Sweet in taste, neutral in nature. It treats traumatic injuries from metal weapons, fractures, internal damage, and promotes muscle regeneration. Current descriptions state it is salty in taste and cold in nature. It reduces swelling, detoxifies carbuncles, sores, and warts. This differs from the description in *Shennong Bencao Jing*, leading to suspicion that it might be a different substance. Additionally, people in Lingnan say there is a stone called Wumingyi, which is extremely rare, and a herb also called Wumingyi, which locals do not value highly. Could it be that the *Shennong Bencao Jing* refers to the stone, while what is currently available is the herb? When used, it is ground with vinegar and applied topically to the affected area. There is also Posuo Shi (Posuo Stone), produced in the South Sea, capable of resolving all toxins. The stone is green, without spots, contains golden flecks, and yields a milky liquid when ground; this is considered superior. Hu people (people from Central/West Asia) particularly treasure it, decorating it with gold to wear as finger rings. Before eating or after finishing a meal, they hold it in their mouth and suck on it several times to prevent poisoning. Currently, a piece the size of a fingernail is worth a hundred taels of gold. People cannot distinguish authenticity easily; only when water-ground drops are placed on fresh blood from a rooster's comb and dissolve into water is it genuine. Commonly known as Mosuo Shi.

Posuo Shi, see details under the entry for Wumingyi.

Shizhonghuangzi (Yellow Substances within Stones), *Shennong Bencao Jing* does not record its origin, stating it is found where Yuyuliang (Hematite) is produced. Currently, it is only found in the valleys of Zhongtiao Mountain, Hezhong Prefecture. The old theory suggests it is the yellow turbid water inside the shell of Yuyuliang before it solidifies into Yuyuliang. The current description states the stone resembles dough pellets, with a purple-black outer skin and a yellow interior, termed "Zhonghuang" (Middle Yellow). The two theories differ slightly. According to Ge Hong's *Baopuzi*: Shizhonghuangzi exists wherever it is found, especially abundant in mountains near water, residing within large rocks. These rocks are often moist and not dry. When struck, dozens of layers are revealed within the rock, showing a reddish-yellow color, fluid-like an egg yolk within a shell. Those who obtain it should drink it immediately; otherwise, it will harden into stone and become unfit for consumption. Breaking one stone may yield up to one sheng (approx. 1 liter) or as little as a few he (approx. 0.2 liters). The method dictates drinking it while it is still unhardened; once hardened, it can be powdered and taken orally. If so, the old theory refers to the substance obtained upon initial breaking. What is currently used is the substance that has hardened over time. It can be harvested at any time.