It is a common misconception that herbal medicines are always plant based materials. While it is true that most of the medicines that herbalists mix together originate from plants, many items do not. Historically any substance that provided a medicinal benefit was used. The issue was not what the material was but what affect it had on the body. Herbal medicines are medicine and often those medicines are composed of non food items. This is similar to modern pharmaceutical medicines which use chemicals and extracts from various animals plants and minerals to provide a medicinal function.
The following are some common mineral based items that are used in traditional Chinese Herbal medicine. These medicinals or "herbs" are rarely used alone, but are often mixed into herbal formulas because they provide medicinal function that plant based herbs do not.