Unfortunately, this is a corruption and is a clever strategy being used to limit his reach and capability and to bring in a kind of poison pill in his teaching. We always wish to avoid pointing fingers, but when asked directly must be truthful. As in this case in particular, there are others at stake who may be trainees carrying away this notion and following his example and having some complications ensue. This is a false notion that this mineral has protective power. Any mineral believed to have healing power can augment human capability and it will help even when partnering with the divine to have an adjunct of this kind whether the object in and of itself is imbued with special powers or simply believed to be so—that is the latter here. So he is not wrong that he feels a benefit, but it is of a modest level in most cases by practitioners working with it and the potential risks do not outweigh any such perceived advantage through relying on it for protection when it cannot deliver.