1. Ineffability, Mystical states are more like states of feeling than intellect, subtle shaded with fine nuances that are difficult to convey in their import and grandeur to another. Consequently, much mystical literature is filled with paradoxes and symbolism.
2. Noetic quality, Mystical experiences are states of knowledge, insight, awareness, revelation, and illumination beyond the grasp of the intellect. There is awareness of unity with the Absolute, of immortality of the soul, of great truths. Time and space are transcended.
3. Transiency, mystical experiences are fleeting in linear time, though they seem to be eternal. Most last a few seconds, some perhaps up to ten minutes. It is rare to sustain a mystical state for more than a half-hour, or perhaps one to two hours at best. Eastern adepts are able to sustain prolonged periods of samadhi, a mystical state of one-pointed concentration; and some reportedly are able to sustain the highest states of nirvana (satori in Zen) and even the rarely attained nirodh.
Many things can produce mystical experiences such as dreams, words, phrases, music, art, sounds, smells, daydreaming, the play of light upon land and sea, nature, or a near-death experience (NDE).
Other techniques include fasting, chanting, dancing, breath control, sexual rites, yoga, and meditation.
