Are the copper and metal pieces used in Chinese medicine for treatment, which contain incomprehensible engravings and writings, considered amulets, especially since some doctors may prescribe them?

That which is worn, and has been proven beneficial through sensory perception and experience built on a scientific basis, or through the reliable reports of trustworthy doctors, then there is no harm in it. As for that which is worn, containing polytheistic writings or unintelligible talismans, or even if it does not contain such writings, but trustworthy doctors deem it medically ineffective, then this falls under the ruling of wearing amulets.