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.
Kaolin ya zama muhimmin kayan ma'adinai ga masana'antu da dama kamar yin takarda, yumbu, roba, injiniyan sinadarai, shafa, magunguna, da kuma tsaron ƙasa.

Masana'antar yumbu ita ce masana'antar farko kuma mafi amfani da ita don amfani da kaolin. Matsakaicin yawan amfani shine kashi 20% zuwa 30% na dabarar. Matsayin kaolin a cikin yumbu shine gabatar da Al2O3, wanda ke da amfani ga samuwar mullite, yana inganta daidaiton sinadarai da ƙarfin sintering. A lokacin sintering, kaolin yana ruɓewa don samar da mullite, yana samar da babban tsarin ƙarfin jiki. Wannan zai iya hana lalacewar samfurin, faɗaɗa zafin wuta, da kuma ba jiki wani matakin fari. A lokaci guda, kaolin yana da wasu ƙarfin plasticity, haɗin kai, dakatarwa da haɗin kai, wanda ke ba da yumbu da fenti mai kyau tare da kyakkyawan tsari, yana sa jikin yumbu mai laushi ya zama mai kyau ga juyawa, grouting da forming. Idan aka yi amfani da shi a cikin wayoyi, yana iya ƙara rufi da rage asarar dielectric.

Ba wai kawai yumbu yana da ƙa'idodi masu tsauri don plasticity, mannewa, raguwar bushewa, ƙarfin bushewa, raguwar sintering, halayen sintering, juriyar wuta, da farin kaolin bayan harbi ba, har ma yana da kaddarorin sinadarai, musamman kasancewar abubuwan chromogenic kamar ƙarfe, titanium, jan ƙarfe, chromium, da manganese, waɗanda ke rage farin bayan harbi kuma suna haifar da tabo.
Bukatar girman barbashi na kaolin gabaɗaya ita ce mafi ƙanƙanta ya fi kyau, don haka laka mai laushi yana da kyakkyawan filastik da ƙarfin bushewa. Duk da haka, don hanyoyin yin siminti waɗanda ke buƙatar saurin siminti, saurin grouting mai sauri, da saurin bushewa, ya zama dole a ƙara girman barbashi na sinadaran. Bugu da ƙari, bambancin da ke cikin lu'ulu'u na Kaolinite a cikin kaolin zai kuma yi tasiri sosai ga aikin fasaha na jikin yumbu. Tare da kyakkyawan lu'ulu'u, ƙarfin lu'ulu'u da haɗin kai zai yi ƙasa, raguwar bushewa zai yi ƙanƙanta, zafin sintering zai yi yawa, kuma za a rage yawan ƙazanta; Akasin haka, ƙarfin lu'ulu'u ya fi girma, raguwar bushewa ya fi girma, zafin sintering ya yi ƙasa, kuma yawan ƙazanta da ya dace shi ma ya fi girma.