Crystal Enlightenment-The Transforming Properties of Crystals and Healing Stones
This book was written in 1985, just a year before our shop opened, and although I was already into Crystals, this book really blew my mind. Katrina really opened up a vast amount of Crystal Knowledge and I think laid the foundation for all the books written since. This is Source Material and hence ageless. Simply written, it's a wonderful introduction for any serious crystal healer.