Michael Gienger (1964-2014) was a well-known expert on crystals and their applications in Europe, a topic in which he had worked since 1988. He has written 20 books on crystal healing in 12 languages, including Healing Stones for the Vital Organs and Crystal Power, Crystal Healing (both in English). Fair Trade Minerals and Gems e.V., situated in Germany, was founded by him.
- Gem Water: How to Prepare and Use More Than 130 Crystal Waters for Therapeutic Treatments
- Healing Crystals: The a - Z Guide to 555 Gemstones
- Healing Stones for the Vital Organs: 83 Crystals with Traditional Chinese Medicine
- Purifying Crystals: How to Clear, Charge and Purify Your Healing Crystals
- Twelve Essential Healing Crystals: Your First Aid Manual for Preventing and Treating Common Ailments from Allergies to Toothache