Powers of gemstones

 Rabbeinu Bachya (Shemos ) It is perfectly in order to accept what Aristotle says as there is no gemstone which does not contain some power given to it by celestial sources. Just as we have been taught in Bereshit Rabbah that there is no herb on earth which does not have its counterpart in the celestial regions providing it with its individual mazzal, so the same is true of the precious stones.