My name is Jeanette Stein and I have written a book titled The Magic of Minerals in Crystal Healing.
I'm a graduate gemmologist and naturopathic herbalist. I have combined these modalities to research crystal healing. I have looked at the nutritional properties of the minerals that make up each crystal and correlated it with the historical healing uses for those crystals.
As the skin is the largest organ of the body and we absorb through the skin, it made sense to me that crystals would work in this way. Nutrition is a world wide accepted modality and gives a simple explanation to why cyrstals heal. This does not take away from the vibrational/energetic properties of the crystals, merely gives another explanation.