Bentonite ma'adinai ne wanda ba na ƙarfe ba, wanda montmorillonite shine babban ɓangaren ma'adinai. Tsarin montmorillonite tsari ne na lu'ulu'u mai nau'in 2: 1 wanda ya ƙunshi tetrahedrons guda biyu na silicon oxygen waɗanda aka yi musu sandwici tare da Layer na aluminum oxide octahedron. Saboda tsarin da aka yi da montmorillonite cell yana da wasu cations, kamar Cu, Mg, Na, K, da sauransu, kuma rawar da waɗannan cations ke takawa tare da montmorillonite cell ba ta da ƙarfi sosai, yana da sauƙin musanya ta wasu cations, yana da kyakkyawan ikon musanya ion. A ƙasashen waje, an yi amfani da shi a sassa sama da 100 a fannoni 24 na masana'antu da noma, tare da sama da samfura 300, shi ya sa mutane ke kiransa "ƙasa ta duniya".

Ana kuma kiran Bentonite da bentonite, bentonite, ko bentonite. Kasar Sin tana da dogon tarihi na haɓakawa da amfani da bentonite, wanda a da ake amfani da shi kawai a matsayin sabulun wanki. Akwai ma'adanai a yankin Renshou na Sichuan shekaru ɗaruruwa da suka gabata, kuma mazauna yankin suna kiran bentonite da foda mai yumbu. Ana amfani da shi sosai amma yana da tarihin sama da shekaru ɗari. Ganowa ta farko a Amurka ya kasance a cikin tsohon yanki na Wyoming. Laka mai chartreuse na iya faɗaɗa zuwa manna bayan ƙara ruwa. Daga baya, mutane suna kiran duk yumbu mai wannan siffa ta bentonite. A zahiri, babban ma'adinan bentonite shine montmorillonite, tare da abun ciki na 85-90%. Wasu kaddarorin bentonite suma montmorillonite ne ke tantance su. Montmorillonite na iya kasancewa cikin launuka daban-daban, kamar kore mai launin rawaya, fari mai launin rawaya, launin toka, fari, da sauransu. Yana iya samar da tubalan da yawa ko ƙasa mai laushi, tare da jin santsi lokacin da aka shafa da yatsu. Bayan ƙara ruwa, girman ƙananan tubalan yana faɗaɗa sau da yawa zuwa sau 20-30, yana bayyana a cikin yanayin dakatarwa a cikin ruwa, kuma a cikin yanayin manna lokacin da babu ruwa kaɗan. Yanayin montmorillonite yana da alaƙa da sinadaran da ke cikinsa da kuma tsarinsa na ciki.