Library

Mifan Shi (Mifan Stone), recorded under the entry for Jiang Shi (Ginger Stone).

Ziran Tong (Natural Copper) is produced in the mountain rocks of Yongzhou where copper emerges. It is now also found in Xinzhou and Huoshan Jun, collected from within copper pits and among stones. Its shape and size are irregular; its color is greenish-yellow like copper. Since it does not require smelting from ore, it is called "Natural Copper." Currently, a variety resembling tangled copper wires is produced in Xinzhou; it is said to naturally flow out within copper mines due to the steaming effect of mountain air, similar to how native silver resembles an old man's beard. This variety is considered best for medicinal use. The specimens from Huoshan Jun are lumpy and resemble copper but are hard and heavy like stone; physicians refer to them as "Shi" (Stone), noting their therapeutic efficacy is weak. They can be collected at any time. Physicians in the south currently describe two or three types of Ziran Tong: one type is as large as hemp or millet seeds, often with multiple facets, linked together, up to the size of a peck measure, with a brilliant, bright color like gold or glaze; this is the highest grade. Another type forms into blocks of varying sizes, also bright and reddish. A third type resembles ginger or iron arrowheads. There are also forms that appear unsmelted, with indeterminate shapes, all originating from copper pits; they shatter easily upon impact, appearing yellow-red or blue-black, and only become true copper after smelting. Although such descriptions offer detailed analysis, the wire-like variety has not been observed. Furthermore, it is reported that many vendors currently pass off "Shi" (Stone) as Natural Copper; when burned, these produce a blue flame, similar to sulfur. These impostors come in two or three varieties: one has a shell like Yuyuliang (Halloysitum Rubrum); when broken, the interior is bright like a mirror, yellowish in color like glaze. Another is greenish-yellow with distinct layers or patterns resembling bundled needles. A third has a fragmented texture like clumped sand. All appear bright like copper, predominantly white-blue with little red, and burn completely to smoke and flame in an instant. Many apothecaries mistakenly identify these as Natural Copper, and market goods are often of this nature. Authentic Natural Copper usually requires calcination; however, since the material fears fire, one can distinguish it by this property alone, without relying on color or shape.

Shiyan (Stone Swallow) is found in Lingling Commandery. Currently, it exists on the sandy beaches beside rivers in Qiyang County, Yongzhou. Its shape resembles a clam but is smaller; it is actually stone. Some claim it grows in mountain caves and flies out during thunderstorms, falling onto the sand to transform into stone, though the accuracy of this is uncertain. Currently, people use it to facilitate childbirth, having the laboring woman hold one in each hand, after which the child is delivered shortly. It can be collected at any time.