You searched for: “abacomancy”
abacomancy (s) (noun), abacomancies (pl)
A divination practice which interprets patterns in dust or in the funerary ashes of the recently deceased to forecast future events: Also known as amathomancy (from the Greek amathos, "sand"), abacomancy is the art and practice of foretelling future events by the observation of omens in patterns of dust, or in the dust, dirt, or sand. Sometimes the diviner would use the ashes of a recently deceased person who was cremated.
The precise origins and method for abacomancies have been lost in time, but it apparently is like most divination techniques, quite ancient.