He studied heavily from that point on, delving quite a bit into the occult. He really believed in telepathy. Telepathy is the ability to see outside ones body, to communicate or travel with one's soul. John Dee did not believe that he was a seer by any means, which is why he delved so deeply into the study of crystals. It is widely believed that one can get visions of the future from crystals. Just like reading the stars or the moon or the sun and tides, which is what the standard horoscope reading is derived from, it is largely believed that one can learn to read crystals. This is what John Dee began to preach and practice. He became a cabalist and studied alchemy. He was so smart and so intuitive and so well known there is even a belief that John Dee was a member of the super secret, highly held society that Leonardo Da Vinci and Newton supposedly belonged to. In fact there is a huge best seller dedicated to the theory of this society, known as the Priory of Sion, called the Da Vinci code, though John Dee is not mentioned in that book, it was believed that he was a member of this secret society, which also dabbled in the occult.
John Dee is revered today for his work with crystals in particular. These days there is a large portion of society that believes and relies on the use of crystal, but more so as crystals being used for healing prowess. The practice of using crystals to heal people is widely know these days as a part of the practice of holistic medicine. There are many books devoted to the subject, as well as radio and television shows. There are doctors that use crystals in their practices. Crystals are sold around the world today and used for many things. There are conventions that travel and sell them or you can order them online, but there are countless people that use crystals in every day life. While all of the uses for crystals and the founding of holistic medicine cannot be traced directly back to John Dee, it is his use of crystals and spreading of John Dee theory of the use of crystals certainly helped attribute to their popularity today. John Dee was probably single handedly responsible for introducing the use of crystals to Europe and the refined world of European aristocracy, and that assuredly had something to do with furthering the cause of the crystal, leading to its widespread healing use today.