Hazrat Ibn Abbas (may Allah be pleased with both of them) says that the purest soil is the soil of the field.

Hasan says that when the time for prayer comes for a person and he does not find water and does not have access to the ground, then he should strike his hands on the saddle of an animal and perform tayammum.

Hazrat Hammad says that tayammum can be performed with soil, lime, stone, and sand.

Hazrat Hammad says that everything upon which you strike your hand is "sa’eed" for you, even the dust lying on the saddle of your animal.

Hazrat Aamir says that tayammum can be performed with grass and with stones or soil from the mountain.

Hazrat Abu Uthman Nahdi narrates that the Messenger of Allah, peace and blessings be upon him, said: Rub your hands on the earth, for it is a means of purification for you.