692. Tayammum can be done on earth, sand, lump of clay or stone but the recommended precaution and better is that if earth is available tayammum should not be performed on anything else. If earth is not available, then it can be performed on sand and if sand is not avalible , then it can be performed on a lump of clay, and in absence of these on a stone.
693.Tayammum is in order with gypsum or limestone; but it is not permissible with plaster and baked lime and mineral stones like agate .
695. If a person can gather some earth by shaking the carpet etc. then to do tayammum with dust particles will not be correct. And similarly if he can make mud dry and obtain earth from it, then tayammum on wet mud will be incorrect and void.
697. If a thing like straw, on which tayammum is void, gets mixed with clay and sand, then tayammum cannot be performed on it. However, if it is so little that it gets lost in the sand or clay, then tayammum with it is valid.
698. If a person does not own anything on which to perform tayammum he should, if possible, get it by purchasing or other similar means.
699. Performing tayammum on mud wall is valid but the recommended precaution is that if dry earth or clay is available, tayammum should not be performed on wet earth or mud.
700. The thing on which a person performs tayammum should be Pak and, if he has no Pak thing on which tayammum would be correct, it is not obligatory for him to offer prayers. He should, however, give its Qadha.
701. If a person was sure that tayammum on a particular thing was valid and he did it accordingly, but came to know later that tayammum performed was void, he would repeat the prayers performed with that tayammum.
702. The thing used for tayammum and its place should not have been usurped. Tayammum on usurped objects like earth, etc, will be void. And also if that thing is his but he take it on the property of other person without obtaining permission and perform tayammum with it , his tayammum is void.
703. Tayammum performed in usurped area or space is not void. Hence, if a person strikes his hands on the earth for tayammum in his own property, and then enters the property of another person without obtaining permission to wipe his hands on his forehead, his tayammum is void.
705. If a person is imprisoned in a usurped place and both the water and earth of that place are usurped, he should pray with tayammum.
707. It is Makrooh to perform tayammum on the earth of a pit, and street dust, or the saline earth, on which a layer of salt has not settled. If, however, a layer of salt has settled on the earth, performance of tayammum on it is void.