Kaolinite mine Aghios Alexandros
MILOS ● Greece
Description: Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra. Rocks that are rich in kaolinite are known as kaolin or china clay.
Kaolinite has a low shrink–swell capacity and a low cation-exchange capacity (1–15 meq/100 g). It is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar.
Because of its iron oxide content, Milos kaolin is not very white.
Etymology: The name is derived from Chinese Kao-Ling, a village near Jingdezhen, Jiangxi province, China. The name entered English in 1727 from the French version of the word: kaolin, following Francois Xavier d'Entrecolles's reports from Jingdezhen.
History on Milos: The use of kaolin on Milos begins in 1800-1100 B.C. during the Bronze Age, with the mining of kaolin for ceramic and pharmaceutical uses.
During the Ottoman rules (1566-1821 A.D.) kaolin was exported for porcelain production.
The industrial exploitation of kaolin starts in 1899 and a processing plant was set up in 1925.
Uses: In many parts of the world, it is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lighter concentrations yield white, yellow or light orange colors.
Commercial grades of kaolin are supplied and transported as dry powder, semi-dry noodle or as liquid slurry.
Miloterranean Geo Experience, Milos Mining History, 2012.