Tayammum (or dry ablution) replaces minor and major ablution if there is no water or in case of illness. It is valid only for a compulsory prayer. The water here is replaced by other natural elements, such as sand, pebbles or earth.
It is therefore permissible to do tayammum by the pure earth and all that is taken from the earth such as sand and stone, as indicated in the Koran and the sunnah.
How to do dry ablutions?
- You have to start by making the intention *
- You have to say "Bismillah"
- to touch both hands on the stone
- run both hands over the face
- then his hands up to the wrists
* One should wipe his face and hands with the intention of being ready and clean for prayer or other worship.