These two narrations indicate the dislike (karahah) of performing tayammum using dust from pathways or frequently trodden areas. Therefore, what remains as suitable for tayammum are elevated and untouched lands, such as ruba (hilltops) and awali (uplands), where water flows down from them, making them preferred for tayammum. The Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, then said: "It is not permissible to perform tayammum with substances other than earth, even if they resemble soil in their softness and powdery nature, such as crushed soapwort (ashnan), aloe (sa'd), or lotus leaves (sidr), and similar materials. It is also not permissible to perform tayammum with ash. However, there is no harm in performing tayammum with chalky white soil (jissiyah) or gypsum soil." Thus, it is established from what has been mentioned that tayammum must be performed using soil, earth, or anything explicitly called soil or earth. These materials that do not fall under the definition of soil or earth are not valid for tayammum. This ruling is further supported by additional evidence.
Commentary #4