Some kaolins are rather plastic but most of them are "short" in working and rather tender.
Found in a crystalline form in china clays and kaolins (p. 107).
The porcelain clays and kaolins contain about half their weight of this earth, to which they owe their most valuable properties.
The kaolins are primary clays formed by the decomposition of felspar and occur in many parts of the world.
As the china clays (kaolins) and ball clays on very careful elutriation all yield a product of the same ultimate composition, viz.
It is a mistake to suppose that all white clays of slight plasticity are china clays or kaolins.
Some kaolins appear to have been formed by weathering and others by subaerial action.
Some kaolins in central Europe appear to have been transported and of secondary origin.
The Kaolins in general appear to consist of alumina and silica in nearly equal proportions.