Kaolinite (Al₂Si₂O₅(OH)₄) is the principal clay mineral — the white-firing clay used for porcelain and china manufacturing for over 1,200 years in Jingdezhen (Jiangxi). Named after the Kao-Ling Hill in Jiangxi where it was first systematically mined for porcelain. Kaolinite forms by chemical weathering of feldspar-rich rocks (granite, gneiss).
Key Facts
- Mohs hardness 2–2.5.
- Triclinic phyllosilicate; microcrystalline platy habit.
- White earthy color, soft and pliable when wet.
- Major industrial source for porcelain, paper coating, ceramics.
- Forms by chemical weathering of K-feldspar — common in tropical lateritic soils.
Notable Localities
Kao-Ling (Jingdezhen, Jiangxi, China) is the type-locality and historical porcelain source. Cornwall (England) hosts industrial china clay. Georgia (USA) supplies major American kaolinite.
Found at these Localities
- Cornwall Mining District (康沃尔矿区)
- Jiangxi (江西)
