divination by means of clear objects
• (n.) Divination by means of a crystal or other transparent body, especially a beryl.
Crys'tal·lo·man`cy noun [ Greek 
Crystallomancy is divination by means of crystals (crystal gazing). Traditionally, the operator first muttered over the crystal certain formulas of prayer, and then gave the crystal (a beryl was preferred) into the hands of a young man or virgin, who received an answer from the spirits within the crystal.
crystallomancy, crystal gazing Divination by means of a crystal or other transparent body, especially a beryl.