This term is used for various forms of divination practiced with the help of rings. The letters of the alphabet are inscribed on a circular table and a ring is suspended above it. It's believed that the ring represents particular letters to spell out the message Needed. This method was used to search for Valen's successor and Theodosius's name was correctly spelt. This form of divination was accompanied by solemn religious services.
An alternative method of dactylomancy involved rings made from gold, silver, lead, iron or copper although there are no recordings of it in detail. The rings were placed on finger nails and used to track down criminals or for the recovery of lost items.