Kaolin wani ma'adinai ne da ba na ƙarfe ba, wanda wani nau'in dutse ne na yumbu da yumbu wanda galibi ya ƙunshi ma'adanai na yumbu na ƙungiyar Kaolinite. Saboda launinsa mai laushi da fari, ana kuma kiransa da ƙasar Baiyun. An sanya masa suna ne bayan ƙauyen Gaoling da ke Jingdezhen, Lardin Jiangxi.

Tsarkakken kaolin ɗinsa fari ne, mai laushi kuma kamar Mollisol, yana da kyakkyawan ƙarfin lantarki, juriya ga wuta da sauran halaye na zahiri da na sinadarai. Mafi yawan abubuwan da ke cikin ma'adinansa sun ƙunshi Kaolinite, halloysite, hydromica, Illite, Montmorillonite, quartz, feldspar da sauran ma'adanai. Ana amfani da Kaolin sosai wajen yin takarda, yumbu, da kayan da ba sa jure wa iska, sai kuma shafa fenti, cika roba, glazes na enamel, da kayan siminti na farin. Ana amfani da ƙaramin adadin a cikin filastik, fenti, launuka, ƙafafun niƙa, fensir, kayan kwalliya na yau da kullun, sabulu, magungunan kashe ƙwari, magunguna, yadi, man fetur, sinadarai, kayan gini, tsaron ƙasa, da sauran sassan masana'antu.

Ma'adanai na Kaolin sun ƙunshi Kaolinite, dickite, lu'u-lu'u, halloysite da sauran ma'adanai na ƙungiyar Kaolinite, kuma babban ɓangaren ma'adinan shine Kaolinite.

Tsarin sinadarai na Crystal na Kaolinite shine 2SiO2 ● Al2O3 ● 2H2O, kuma tsarin sinadaransa na ka'idar shine 46.54% SiO2, 39.5% Al2O3, 13.96% H2O. Ma'adanai na Kaolin suna cikin silicate mai layi 1:1, kuma lu'ulu'u galibi ya ƙunshi silica tetrahedron da alumina Octahedron. Ana haɗa silica tetrahedron tare da alkiblar girma biyu ta hanyar raba kusurwar vertex don samar da layin grid mai hexagonal, kuma iskar oxygen mai tsayi wanda kowane tetrahedron silica ba ya raba yana fuskantar gefe ɗaya; Layin naúrar nau'in 1:1 ya ƙunshi layin tetrahedron na silicon oxide da layin aluminum oxide Octahedron, waɗanda ke raba tip oxygen na layin tetrahedron na silicon oxide.